Access device

ABSTRACT

An access device for placing a medical article within a body space includes a needle, a dilator, and a medical article. The needle can include an elongated needle body with a distal end and a hub from which the needle body extends. The elongated needle body can include at least one side fenestration and an outer diameter. The dilator can be slideably disposed on the needle body and include a dilator hub and an elongated dilator shaft that extends from the dilator hub. The dilator shaft can include at least one side fenestration in communication with the needle side fenestration. The dilator shaft can also include an inner diameter that is less than the outer diameter of the needle. The medical article can include a tubular section and a hub. The tubular section can be disposed on the dilator and define a space between the medical article and the dilator in communication with the needle side fenestration through the dilator side fenestration. At a least portion of the medical article can be configured to allow visual determination of the presence of a body fluid within the space.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/577,653, filed 7 Aug. 2012, now issued as U.S.Pat. No. 8,956,327, which claims the benefit of International PatentApplication No. PCT/US2011/24097, filed 8 Feb. 2011, which claims thepriority benefit under 35 U.S.C. § 119(e) to U.S. Provisional PatentApplication Ser. No. 61/302,486 (filed 8 Feb. 2010), the entirety ofwhich being hereby expressly incorporated by reference herein.

BACKGROUND

Field of the Invention

This invention is generally directed to access devices for introducingand/or delivering a medical article (such as, for example, a catheter,cannula, sheath, etc.) into a body space, such as, for example, anartery, vein, vessel, body cavity, or drainage site.

Description of the Related Art

A preferred non-surgical method for inserting a catheter or vascularsheath into a blood vessel involves the use of the Seldinger or amodified Seldinger technique, which includes an access needle that isinserted into a patient's blood vessel. A guidewire is inserted throughthe needle and into the vessel. The needle is removed, and a dilator andsheath in combination or separately are then inserted over theguidewire. The dilator and sheath, together or separately, are theninserted a short distance through the tissue into the vessel, afterwhich the dilator and guidewire are removed and discarded. A catheter orother medical article may then be inserted through the sheath into thevessel to a desired location, or the sheath may simply be left in thevessel.

A number of vascular access devices are known. U.S. Pat. Nos. 4,241,019,4,289,450, 4,756,230, 4,978,334, 5,124,544, 5,424,410, 5,312,355,5,212,052, 5,558,132, 5,885,217, 6,120,460, 6,179,823, 6,210,332,6,726,659 and 7,025,746 disclose examples of such devices. None of thesedevices, however, has the ease and safety of use that physicians andother healthcare providers would prefer. Thus, there exists a need foran easier-to-use and safer vascular access device, especially one thatwould clearly and promptly indicate when a blood vessel has beenpunctured and one that would reduce accidental needle sticks and otherattendant risks of over-wire vascular access.

SUMMARY

The described embodiments involve several features for an access deviceuseful for the delivery of a catheter or sheath into a space within apatient's body, such as, for example, a blood vessel or drainage site.Without limiting the scope of this invention, its more prominentfeatures will be discussed briefly. After considering this discussion,and particularly after reading the Detailed Description of the PreferredEmbodiments section below in combination with this section, one willunderstand how the features and aspects of these embodiments provideseveral advantages over prior access devices.

In one embodiment, an access device for placing a medical article withina body space includes a needle, a dilator, and a medical article. Theneedle can include an elongated needle body with a distal end and a hubfrom which the needle body extends. The elongated needle body caninclude at least one side fenestration and an outer diameter. Thedilator can be slideably disposed on the needle body and include adilator hub and an elongated dilator shaft that extends from the dilatorhub. The dilator shaft can include at least one side fenestration incommunication with the needle side fenestration. The dilator shaft canalso include an inner diameter that is less than the outer diameter ofthe needle. The medical article can include a tubular section and a hub.The tubular section can be disposed on the dilator and define a spacebetween the medical article and the dilator in communication with theneedle side fenestration through the dilator side fenestration. At aleast portion of the medical article can be configured to allow visualdetermination of the presence of a body fluid within the space.

In another embodiment an access device for placing a medical articlewithin a body space can include a needle, a dilator, and a medicalarticle. The needle can include an elongated needle body with a distalend and a hub from which the needle body extends. The dilator can beslideably disposed on the needle body and include a dilator hub and anelongated dilator shaft that extends from the dilator hub. The dilatorshaft can include at least one side fenestration in communication withthe needle side fenestration and a raised ridge through which thefenestration passes. The medical article includes a tubular section anda hub. The tubular section can be disposed on the dilator and define aspace between the medical article and the dilator in communication withthe needle side fenestration through the dilator side fenestration. At aleast portion of the medical article can be configured to allow visualdetermination of the presence of a body fluid within the space.

In yet another embodiment, an access device for placing a medicalarticle within a body space can include a needle, a dilator, and amedical article. The needle can include an elongated needle body with adistal end and a hub from which the needle body extends. The dilator canbe slideably disposed on the needle body and include a dilator hub andan elongated dilator shaft that extends from the dilator hub to a distalend. The dilator shaft can include at least one side fenestration incommunication with the needle side fenestration, and the dilator distalend can taper at approximately 30 degrees. The medical article includesa tubular section and a hub. The tubular section can be disposed on thedilator and define a space between the medical article and the dilatorin communication with the needle side fenestration through the dilatorside fenestration. At a least portion of the medical article can beconfigured to allow visual determination of the presence of a body fluidwithin the space.

In a further embodiment, an access device for placing a medical articlewithin a body space can include a needle, a dilator, a sealing piece,and a medical article. The needle can include an elongated needle bodywith a distal end and a hub from which the needle body extends. Thedilator can be slideably disposed on the needle body and include adilator hub and an elongated dilator shaft that extends from the dilatorhub to a distal end. The dilator shaft can include at least one sidefenestration in communication with the needle side fenestration. Thesealing piece can be slideably disposed on the needle body and bedisposed between the dilator and the needle to inhibit fluid flowbetween the dilator and needle hubs. The medical article includes atubular section and a hub. The tubular section can be disposed on thedilator and define a space between the medical article and the dilatorin communication with the needle side fenestration through the dilatorside fenestration. At a least portion of the medical article can beconfigured to allow visual determination of the presence of a body fluidwithin the space.

In another embodiment, a method of accessing a body cavity is provided.A needle with a hollow bore, a side fenestration, and a needle hub canbe inserted into a body cavity. A dilator with a side fenestration and adilator hub can be axially disposed on the needle and a medical articlecan be axially disposed on the dilator. A body fluid can be drawn fromthe body cavity through the needle bore to the needle side fenestration.Further, the body fluid can be drawn through the needle sidefenestration and through the dilator side fenestration into a spacebetween the dilator and the medical article. Movement of the body fluidproximally between the needle and the dilator hub can be inhibited.

In yet another embodiment an access device for placing a medical articlewithin a body space can include a guidewire section, a needle, adilator, and two locking mechanisms. The guidewire section can include aguidewire and a guidewire hub. The needle can be disposed on theguidewire and have an elongated needle body with a distal end and a hubfrom which the needle body extends. The dilator can be disposed on theneedle body, the needle and the dilator being moveable relative to eachother from a first position, wherein the distal end of the needle liesdistal of the dilator, and a second position wherein the distal end ofthe needle lies within the dilator. The dilator can also include adilator hub and an elongated dilator shaft that extends from the dilatorhub. The first locking mechanism can operate between the needle and thedilator, and can include a portion spaced from the dilator that inhibitsmovement of the needle relative to the dilator when in the secondposition. The first locking mechanism can be configured to allowmovement of the needle from the first position toward the secondposition without engagement by the locking mechanism so as to lessenresistance to the movement. The second locking mechanism can operatebetween the dilator and the guidewire, and can include a T-shapedlocking section disposed on the guidewire that interengages with theguidewire hub to form a reversible snap-fit grip.

These and other aspects of the present invention will become readilyapparent to those skilled in the art from the following detaileddescription of the preferred embodiments, which refers to the attachedfigures. The invention is not limited, however, to the particularembodiments that are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the access devicedisclosed herein are described below with reference to the drawings ofpreferred embodiments, which are intended to illustrate and not to limitthe invention. Additionally, from figure to figure, the same referencenumerals have been used to designate the same components of anillustrated embodiment. Like components between the illustratedembodiments are similarly noted as the same reference numbers with aletter suffix to indicate another embodiment. The following is a briefdescription of each of the drawings.

FIG. 1A is a perspective view of a preferred embodiment of an accessdevice configured in accordance with the present invention and shows apre-loaded guidewire section coaxially aligned with a needle, a dilator,and a medical article.

FIG. 1B is a plan view of the embodiment depicted in FIG. 1A.

FIG. 2A is a plan view of the needle from FIG. 1A and shows afenestration near a distal end.

FIG. 2B is a side view of the needle from FIG. 1A and shows a fin near aproximal end.

FIG. 2C is a cross-sectional view taken along the lines 2C-2C in FIG.2A.

FIG. 2D is an enlarged plan view of a portion of the needle of FIG. 2Aand shows the fenestration.

FIG. 2E is an enlarged plan view of the needle hub of the needle of FIG.2A.

FIG. 2F is an enlarged side view of the needle hub of the needle of FIG.2A.

FIG. 2G is an enlarged proximal end view of the needle hub of the needleof FIG. 2A.

FIG. 3A is a plan view of the dilator from FIG. 1A and shows afenestration near a distal end. FIG. 3A also shows longitudinallyarranged grooves in the luer surface for venting air from between thedilator and sheath.

FIG. 3B is a cross-sectional view taken along the lines 3B-3B in FIG.3A.

FIG. 3C is an enlarged plan view of a portion of the dilator from FIG.3A and shows the fenestration and longitudinal channel.

FIG. 3D is an enlarged end view of the dilator hub from FIG. 3A.

FIG. 3E is a perspective view of another embodiment of the dilator hubthat includes a locking spin nut configured to secure to a sheath thathas a corresponding screw thread.

FIG. 3F is a cross-sectional view taken along the lines 3F-3F in FIG. 3Aand shows the grooves equally spaced about the circumference of the luersurface.

FIG. 4A is a plan view of the sheath from FIG. 1A and shows a sheath hubconnected to a proximal end of a sheath.

FIG. 4B is a cross-sectional view taken along the lines 4B-4B in FIG.4A.

FIG. 4C is an enlarged end view of the sheath from FIG. 4A.

FIG. 4D is an enlarged perspective view of a proximal portion of thesheath from FIG. 4A.

FIG. 5A is a perspective view of the guidewire section from FIG. 1A andshows a guidewire hub connected to a proximal end of a guidewire.

FIG. 5B is a plan view of the guidewire section of the embodimentdepicted in FIG. 5A.

FIG. 6A is a perspective view of a track from FIG. 1A.

FIG. 6B is a plan view of the track in FIG. 6A and shows a lockingmechanism for locking the needle relative to the dilator.

FIG. 6C is a side view of the track in FIG. 6B.

FIG. 6D an enlarged view of the locking mechanism from FIG. 6B.

FIG. 6E is an enlarged view of another locking mechanism that locks theguidewire section in a pre-loaded state.

FIG. 7A is a plan view of the access device from FIG. 1A and shows thelocking mechanism from FIG. 6E with the guidewire section locked to thetrack in the pre-loaded state.

FIG. 7B is a side view of the access device and locking mechanism fromFIG. 7A.

FIG. 7C is a cross-sectional view through the access device of FIG. 7Aand shows the guidewire hub disposed between an element and stop of thetrack.

FIG. 7D is an enlarged end view of the access device from FIG. 7B andshows two arms extending from the track and around at least a portion ofthe guidewire hub.

FIG. 8A is a plan view of the embodiment depicted in FIG. 1Aillustrating the insertion of the distal end of the access device into apatient.

FIG. 8B is an enlarged view of the embodiment depicted in FIG. 8Afocusing on the area of the access device adjacent to the patient.

FIG. 8C is an enlarged view of a portion of the embodiment depicted inFIG. 8B and illustrates the needle opening or fenestration aligned withthe dilator opening or fenestration in hidden lines.

FIG. 8D is an enlarged cross-sectional view of a portion of theembodiment depicted in FIG. 8C and shows the needle opening orfenestration aligned with the dilator opening or fenestration so as toallow fluid to flow from inside the needle to a channel formed betweenthe sheath and dilator.

FIG. 8E is a graph showing the rate fluid is drawn up a channel with agap height width of 0.002 inches.

FIG. 8F is a graph showing the rate fluid is drawn up a channel with agap height width of 0.001 inches.

FIG. 8G is a graph showing the rate fluid is drawn up a channel with agap height width of 0.0005 inches.

FIG. 8H is an enlarged cross-sectional view of a portion of theembodiment depicted in FIG. 8C taken through a region distal of thechannel in the dilator.

FIG. 8I is an enlarged view of the embodiment depicted in FIG. 8Afocusing on the area where the needle hub is locked to the dilator hubwhen the needle hub is in the first position.

FIG. 8J is a cross-sectional view of the embodiment depicted in FIG. 8I.

FIG. 9A is a side view of the embodiment depicted in FIG. 1Aillustrating the guidewire advanced from the needle tip in a distaldirection.

FIG. 9B is an enlarged view of the embodiment depicted in FIG. 9Afocusing on the area where the guidewire hub is locked to the needle hubwhen the needle hub is in the first position.

FIG. 9C is a cross-sectional view of the embodiment depicted in FIG. 9B.

FIG. 10A is a side view of the embodiment depicted in FIG. 1Aillustrating the dilator and sheath being advanced distally relative tothe needle body from the position illustrated in FIG. 9A.

FIG. 10B is an enlarged rear view of the embodiment depicted in FIG. 10Afocusing on the area where the needle hub is locked to the track whenthe needle hub is in the second position.

FIG. 11A is a side view of the embodiment depicted in FIG. 1Aillustrating the removal of the guidewire, needle body, and dilator fromthe sheath.

FIG. 11B is an enlarged view of the portion of the embodimentillustrated in FIG. 11A showing the needle tip covered by the dilatorduring removal of the guidewire, needle body, and dilator from thesheath.

FIG. 12A is an enlarged plan view that illustrates another embodiment ofthe aligned openings or fenestrations in the needle and dilator.

FIG. 12B is an enlarged cross-sectional view along lines 13B-13B in FIG.12A and shows the needle opening or fenestration aligned with thedilator opening or fenestration so as to allow fluid to flow from insidethe needle to a channel formed between the sheath and dilator.

FIG. 13A is an enlarged plan view that illustrates another embodiment ofthe aligned openings or fenestrations in the needle and dilator.

FIG. 13B is an enlarged cross-sectional view along lines 13B-13B in FIG.13A and shows the needle opening or fenestration aligned with thedilator opening or fenestration so as to allow fluid to flow from insidethe needle to a channel formed between the sheath and dilator

FIG. 14A is an enlarged plan view that illustrates another embodiment ofthe channel formed between the dilator and the sheath.

FIG. 14B is a cross-sectional view along lines 14B-14B in FIG. 14A andshows the thickness of the channel extending into the sheath.

FIG. 15A is an enlarged plan view that illustrates another embodiment ofthe channel formed between the dilator and the sheath.

FIG. 15B is a cross-sectional view along lines 15B-15B in FIG. 15A andshows the thickness of the channel extending into both the dilator andthe sheath.

FIG. 16A is an enlarged plan view that illustrates another embodiment ofthe channel formed between the dilator and the sheath.

FIG. 16B is a cross-sectional view along lines 16B-16B in FIG. 15A andshows a plurality of equally spaced channels in the form of splinesextending into the dilator.

FIG. 17 is an enlarged cross-sectional view through another embodimentof the access device and shows the channel formed between a sheath and adilator that have dissimilar shapes.

FIG. 18A is an enlarged plan view of a portion of another embodiment ofthe access device and illustrates another embodiment of a channel thistime formed between the needle and the dilator.

FIG. 18B is an enlarged cross-sectional view through the embodiment ofFIG. 18A taken at 18B-18B.

FIG. 18C is an enlarged cross-sectional view through the embodiment ofFIG. 18A taken at 18C-18C.

FIG. 18D is an enlarged perspective view of a needle hub configured toform part of the needle depicted in FIG. 18A.

FIG. 18E is a plan view of the dilator of FIG. 18A.

FIG. 19A is an enlarged cross-sectional view of another embodiment of anaccess device showing portions of a needle hub, a dilator hub, and aninsert.

FIG. 19B is an enlarged cross-section view of the access device of FIG.19A, wherein an insert is not fully inserted.

FIG. 19C is an enlarged view of an insert of the access device of FIG.19A.

FIG. 20A is a plan view of a distal portion of another embodiment of adilator.

FIG. 20B is a cross-sectional view of the distal portion of the dilatorof FIG. 20A, with a fenestration in phantom.

FIG. 20C is an enlarged view of a section of the dilator of FIG. 20Btaken at 20C-20C.

FIG. 20D is an enlarged view of a section of the dilator of FIG. 20Btaken at 20D-20D.

FIG. 20E is a side view of the dilator of FIG. 20A, with interiorfeatures in phantom.

FIG. 21A is a side view of another embodiment of a needle.

FIG. 21B is an enlarged view of a distal end of the needle of FIG. 21A.

FIG. 22A is a perspective view of another embodiment of a track.

FIG. 22B is a plan view of the track of FIG. 22A.

FIG. 22C is a side view of the track of FIG. 22A

FIG. 22D is an enlarged view of a section of the track of FIG. 22A takenat 22D-22D.

FIG. 23A is a perspective view of another embodiment of a guidewire hub.

FIG. 23B is a bottom view of the guidewire hub of FIG. 23A.

FIG. 24A is a proximal end view of another embodiment of a sheath.

FIG. 24B is a plan view of the sheath of FIG. 24A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure provides an access device for the delivery of amedical article (e.g., catheter or sheath) to a blood vessel or drainagesite. FIG. 1A illustrates an access device 20 that is configured to beinserted into a blood vessel (e.g., a vein or an artery) in accordancewith a preferred embodiment of the present invention. While the accessdevice is described below in this context (i.e., for vascular access),the access device also can be used to access and place a medical article(e.g., catheter or sheath) into other locations within a patient's body(e.g., a drainage site) and for other purposes (e.g., for draining anabscess).

The present embodiment of the access device is disclosed in the contextof placing an exemplary single-piece, tubular medical article into abody space within a patient. Once placed, the tubular article can thenbe used to receive other medical articles (e.g., catheters, guidewires,etc.) to provide access into the body space and/or be used to provide apassage way for introducing fluids into the body space or removing(e.g., draining) fluids from the body space. In the illustratedembodiment, the tubular medical article is a sheath or catheter that isconfigured primarily to provide a fluid passage into a vein. Theprinciples of the present invention, however, are not limited to theplacement of single piece sheaths or catheters, or to the subsequentinsertion of a medical article via the sheath or catheter. Instead, itwill be understood by one of skill in this art, in light of the presentdisclosure, that the access device disclosed herein also can besuccessfully utilized in connection with placing one or more other typesof medical articles, including other types of sheaths, fluid drainageand delivery tubes, and single or multi-lumen catheters directly in thepatient or indirectly via another medical article.

For example, but without limitation, the access device disclosed hereincan also be configured to directly or indirectly place central venouscatheters, peripherally inserted central catheters, hemodialysiscatheters, surgical drainage tubes, tear-away sheaths, multi-piecesheaths, scopes, as well as electrical conduit for wires or cablesconnected to external or implanted electronic devices or sensors. Asexplained above, the medical articles listed above may be directlyplaced in the patient via the dilator, needle, and guidewire of theaccess device or subsequently placed within the patient via a medicalarticle that was placed within the patient via the dilator, needle, andguidewire of the access device.

Further, the embodiments disclosed herein are not limited to co-axialinsertion of a single medical article. For example, two catheters may beinserted in the patient via an inserted sheath or a second catheter maybe inserted in the patient via an inserted first catheter. Further, inaddition to providing a conduit into the vessel or other body space, themedical article inserted via the dilator, needle, and guidewire can forma lumen that is in addition to the lumen(s) of the subsequently insertedmedical article. One skilled in the art can also find additionalapplications for the devices and systems disclosed herein. Thus, theillustration and description of the access device in connection with asheath (e.g., for micro puncture applications) is merely exemplary ofone possible application of the access device.

FIGS. 1A and 1B illustrated a preferred embodiment of an access device20. The access device 20 comprises a needle 22, a dilator 24, and asheath 26. In the illustrated embodiment, the access device alsoincludes a guidewire section 28 and a track 30. As best seen in FIG. 1B,the dilator 24 is preferably coaxially mounted on the needle 22, and thesheath 26 is coaxially mounted on the dilator 24. The telescoping natureof the access device's components can also be accomplished by arrangingthe components with their axes arranged substantially parallel ratherthan coaxially (e.g., a monorail-type design).

Each of these components includes a luminal fitting at a terminal end ortransition (i.e., a hub) and elongated structure that extends from thefitting. Thus, in the illustrated embodiment, the needle 22 includes aneedle body 32 that extends distally from the needle hub 34, the dilator24 includes a dilator shaft 36 that extends distally from a dilator hub38, and the sheath 26 includes a sheath body 40 that extends distallyfrom a sheath hub 42. The guidewire section 28 comprises a guidewire 44and preferably a guidewire hub or cap 46. In the illustrated embodiment,the guidewire hub 46 is disposed on the proximal end of the guidewire44; however, in other applications, the hub 46 can be disposed at alocation between the ends of the guidewire 44.

FIGS. 2A-2G illustrate the needle body 32 and needle hub 34 of theneedle 22, which are configured in accordance with a preferredembodiment of the access device, in isolation from the other componentsof the access device 20. As best seen in FIGS. 2A and 2B, the needle hub34 is disposed on a proximal end of the needle body 32. The needle body32 terminates at a distal end near a distal portion 50 of the needle 22,and the needle hub 34 lies at a proximal portion 52 of the needle 22.

The needle body 32 preferably has an elongated tubular shape having acircular, constant-diameter inner bore and a circular, constant-diameterexterior surface. In other embodiments, however, the needle body 32 canhave other bore and exterior shapes (such as, for example, but withoutlimitation, an oval cross-sectional shape). The interior or exterior ofthe needle can also include grooves or channels. The grooves or channelsmay guide fluids within the needle bore either around or to certainstructures of the needle 22 or within the needle 22 (e.g., around theguidewire). In some embodiments, the grooves or channels may assist inmaintaining a desired orientation of the needle 22 with respect to thedilator.

The needle body 32 has a sufficiently long length to access a targetedsubcutaneous body space and has a sufficient gauge size to withstand theinsertion forces when accessing the body space without causing unduetrauma. For many applications, the needle body can have a length between3-20 cm, and more preferably between 3-10 cm. For example, to access abody space (e.g., a vessel) in the thorax of an adult human, the needlebody 32 preferably has a length of 7 cm or greater, and more preferablyhas a length of 9 cm or greater, and most preferably has a length of 9to 10 cm. The size of the needle preferably is 18 gauge or smaller, andmore preferably between 18-28 gauge, and most preferably between 18-26gauge for micro-puncture applications (peripheral IVs). For applicationswith a neonate, the length and gauge of the needle body 32 should besignificantly shorter and smaller, for example preferably between 3-4 cmand between 26-28 gauge.

As best seen in FIGS. 2A and 2D, the needle body 32 includes at leastone fenestration or opening 56 near a distal end of the needle body 32.The fenestration 56 extends through the wall of the needle body 32 andcan have a variety of shapes and orientations on the needle body 32, asdescribed in detail below. In addition, the needle body 32 can have abevel tip 54 disposed on the distal portion 50.

As is illustrated in FIGS. 2A and 2B, a fin 58 is preferably disposed ata circumferential location around the needle hub 34 that is aligned withthe circumferential locations of the bevel on the needle tip and theopening or fenestration 56 in the needle. That is, the fin 58 is indexedwith the bevel and fenestration. During use, the physician or healthcareprovider can determine the orientation of the beveled needle tip (andthe fenestration 56) by noting the orientation of the exposed fin 58even though the bevel is inside the vessel and the fenestration iscovered by the sheath and/or dilator. For example, in the illustratedembodiment, an orientation of the fin 58 away from the patient coincideswith a bevel up orientation of the needle tip within the vessel. Thefenestration 56 is also on the same side as the fin 58, as seen in FIG.2C.

The fin 58 also provides a grasping region to manipulate the needle hub34. For example, a physician or healthcare provider can place an indexfinger and thumb on the sides of the fin 58 to stabilize the needle hub34, relative to the dilator 24 and/or sheath 26. In the illustratedembodiment, as the dilator/sheath slides distally over the needle, theneedle hub 34 slides relatively along the track 30 between a firstposition 121 and a second position 123 (example portions illustrated inFIG. 6A). The fin 58 can be held when performing the insertion step(which will be described below). In addition, the fin 58 can be used tostabilize the needle hub 34 while rotating the dilator hub 38.Furthermore, the fin 58 can be used by a physician or healthcareprovider as an aid to grasp the access device 20 when the needle hub 34is disposed at any position along the track 30.

FIG. 2D is an enlarged view of the side opening or fenestration 56 inthe needle body 32. The one or more fenestration 56 provides a paththrough the side of the needle body 32. The fenestration 56 illustratedin FIG. 2D has an oblong shape. The shape of the side opening 56,however, is not limited to the illustrated embodiment and may be round,oblong, square, or another shape.

With specific reference now to FIGS. 2E-2G, the needle hub 34 preferablyincludes locking structures at the proximal portion and distal portionof the needle hub 34. These locking structures may be a luer-thread-typeor another type of connections.

The locking structure on the proximal portion 52 of the needle hub 34allows the physician or healthcare provider to secure another medicalarticle to the proximal end of the needle hub 34. For example, theneedle hub 34 in the illustrated embodiment includes an annular flangeor lip 63. The lip 63 is threaded to allow the needle hub 34 to attachto other medical articles with a corresponding luer-nut locking feature.Additionally, a physician or healthcare provider may attach a syringe ormonitoring equipment to the locking structure on the proximal end toperform other procedures as desired. The needle hub 34 can also includea septum at its proximal end and/or a side port if these features aredesirably for a particular application.

The locking structure on the distal portion of the needle hub 34 allowsthe physician or healthcare provider, for example, to lock the needlehub 34 to the dilator hub 38 when the needle hub 34 is in the firstposition 121. In the illustrated embodiment, the locking structureincludes a latch element 66 on the needle hub 34. The latch element 66releasably locks the needle hub 34 to the dilator hub 38. The lockingstructure allows the healthcare provider to advance the needle into apatient while grasping the needle hub 34, the dilator hub 38 or both.

As explained below in greater detail, the guidewire 44 is introducedthrough a hollow portion 62 of the needle hub 34, through the needlebody 32, and into a punctured vessel. The guidewire 44 allows thehealthcare provider to guide the dilator 24 and sheath 26 into thevessel.

The needle hub 34 may also comprise two tangs 68 that allow the needlehub 34 to slide along the track 30 between a first position 121 and asecond position 123. While in the preferred embodiment the two tangs 68of the needle hub 34 are engaged with the track 30 between the firstposition 121 and the second position 123, in other embodiments theneedle hub 34 is only engaged with the track 30 over a portion of thelength of the track 30 between the first position 121 and the secondposition 123. The sliding interconnection between the track 30 and theneedle hub 34 also can be accomplished using other cooperatingstructures (e.g., a corresponding pin and tail of dovetail connection).

FIG. 3A is a plan view of the dilator 24 of the embodiment depicted inFIG. 1A. FIG. 3B is a cross-sectional view of the dilator 24 of theembodiment depicted in FIG. 3A, taken along line 3B-3B. As shown inFIGS. 3A and 3B, the illustrated dilator 24 comprises a dilator shaft36, a dilator hub 38, a distal region 70, and a proximal region 72. Inthe illustrated embodiment, the dilator shaft 36 includes a sideopenings or fenestrations 74; however, in other embodiments, the dilatorshaft 36 can include fewer or greater numbers of fenestrations 74. Forexample, the dilator shaft 36 may not include a fenestration 74 where ablood flash chamber(s) is disposed within the dilator (as will bedescribed in more detail below).

The dilator hub 38 may comprise one or more vents. In the illustratedembodiments, the vents in the dilator hub 38 are formed by grooves 75.Additionally, the dilator shaft 36 may comprise one or more longitudinalchannels formed in the outer surface of the dilator shaft 36. In theillustrated embodiment, the channel is an open channel. The side wallsof the open channel are formed by ridges 76. In the illustratedembodiment, the ridges 76 define generally smooth, arcuate exteriorsurfaces that interface with the sheath 26; however, in otherembodiments, the ridges can have other shapes (e.g., can define morepronounced apexes). Once assembled within a sheath body 40, the openchannel in the dilator shaft 36 is closed by the inside diameter of thesheath body 40.

FIG. 3C is an enlarged plan view of a portion of the embodimentillustrated in FIG. 3A. As noted above, the illustrated dilator shaft 36comprises one or more side openings 74 and one or more channels formedbetween ridges 76. The side opening or fenestration 74 provides a fluidpath through the side of the dilator shaft 36. The shape of the sideopening 74 is not limited to the illustrated embodiment and may beround, oblong, square, or have another shape. The opening orfenestration 74 illustrated in FIG. 3C has an oblong shape.

In the illustrated embodiment, the opening 74 in the dilator shaft 36has an oblong shape with its major axis being non-parallel relative tothe major axis of the oblong opening 56 in the needle 22. For examplethe needle opening 56 may extend in a longitudinal direction and thedilator opening 74 may extend in a circumferential direction or viceversa. In other words, the long axis of the dilator opening 74 isdisposed generally perpendicular to the long axis of the needle opening56. As explained in connection with additional embodiments below, theseopenings 56, 76 can have other shapes, sizes and orientations thatpreferably obtain a significant degree of overlap to account formanufacturing tolerances and rotational misalignments. For this reason,it is preferred that one of the fenestrations has a greater dimension inat least one direction than the other one of the fenestrations in thesame direction. Accordingly, in the illustrated embodiment, the needlefenestration 56 has a longer longitudinal dimension than thelongitudinal dimension of the dilator fenestration 74.

The channel formed between the ridges 76 extends in a proximal directionfrom a point distal to the opening 74. The ridges 76 in the illustratedembodiment are disposed along the dilator shaft 36 and on opposite sidesof the dilator shaft 36 so as to balance the dilator shaft 36 within thesheath. In the illustrated embodiment, the ridges 76 form two channelsthere between. Balancing the dilator within the sheath allows thedilator to apply equal pressure to the inside circumference of thesheath.

The dilator hub 38 may include locking structures at the proximal region72 and the distal region of the dilator 24. Each locking structure maybe a luer type or other type of connection. In the illustratedembodiment, the dilator hub 38 comprises a first luer connection 78, asecond luer connection 80, a lip 77, and a base 79. The first luerconnection 78 engages to the needle hub 34 on the needle 22 illustratedin FIG. 2E. The second luer connection 80 is disposed distal to thefirst luer connection 78. In some embodiments, the second luerconnection 80 (e.g., a male luer slip connector) can be configured toengage to the sheath hub 42 (e.g., a female luer slip connector) on thesheath 26 illustrated in FIG. 1A. Additionally, the male-female lureslip connectors on these components can be reversed.

FIG. 3D is an enlarged proximal end view of the dilator 24 of FIG. 3A.As shown most clearly in FIG. 3D, the dilator hub 38 comprises anopening 82 that releasably engages the latch element 66 on the needlehub 34 illustrated in FIGS. 2E-2F to secure the dilator hub 38 to theneedle hub 34 when the needle hub 34 is in the first position 121.Again, the male-female lure slip connectors on the dilator hub and theneedle hub 34 can also be reversed in other embodiments.

The color of the dilator 24 may be selected to enhance the contrastbetween the blood or other fluid and the dilator 24. During blood flash,for example, blood is observed flowing between the dilator 24 and thesheath to confirm proper placement of the needle in a blood vessel. Toincrease the visibility of the fluid as the fluid flows between thesheath and dilator 24, the sheath is preferably manufactured from aclear or transparent material with the dilator 24 having a color thatcontrasts with the color of the fluid. For example, the dilator 24 mayhave a white color to enhance its contrast with red blood. Other colorsof dilator 24 could be employed depending on the color of the fluid andthe degree of contrast desired. Further, only a portion of the dilatorin the region of the blood flash can have the contrasting color with theremainder having a different color. For embodiments that have a channelformed between the needle and dilator 24, the dilator 24 may bemanufactured of a clear or transparent material similar to the sheath toallow the physician to observe the blood flash through both the sheathand dilator 24.

FIG. 3E is an enlarged perspective view of another embodiment of adilator hub 38A. The dilator hub 38A is similar to the dilator hub 38illustrated in FIG. 3A except that the dilator hub 38A further includesa spin nut or collar 84. The proximal end of the spin nut 84 rotatesabout an annular groove 73 in the dilator hub 38 (see FIG. 3A). Oncedisposed within the annular groove 73, the spin nut 84 is inhibited frommoving in the distal direction but is free to rotate about the dilatorhub 38A. The spin nut 84 can have an interengaging element that locks toa corresponding interengaging element on the sheath 26. In theillustrated embodiment, the spin nut 84 includes an internal threadwhich engages with an external thread on the sheath hub 42 on the sheath26 illustrated in FIG. 1A.

The dilator 24 or sheath 26 may separately, or together, form one ormore passages to allow air or gas to escape or vent from between thedilator 24 and sheath 26 and/or between the needle and the dilator. Theone or more passages may further be sized to inhibit the flow of aliquid, such as blood, while allowing air to pass therethrough. The oneor more passages may be in the wall of the sheath 26, the sheath hub,the dilator hub 38, an exposed section of the dilator shaft, and/orformed between adjacent surfaces of the dilator 24 and sheath 26. Forexample, FIG. 3A shows longitudinally arranged grooves 75 that areformed between adjacent surfaces of the dilator 24 and sheath 26. Suchventing passages can also be labyrinth. The adjacent surfaces form aluer slip connection between the sheath 26 and dilator 24.

FIG. 3F is a cross-sectional view taken along lines 3F-3F in FIG. 3A andshows the grooves 75 equally spaced, though not required to be equallyspaced, about the circumference of the luer slip surface. The grooves 75are sized to allow air to escape from between the dilator and themedical article, such as a sheath, when the blood flash occurs. Asmentioned above, the one or more passages need not be in the form of asurface groove 75 and instead may be in the form of an opening orpassageway.

In the illustrated embodiment, the one or more passages allow air topass through the luer connection between the sheath and dilator hubs. Inthe illustrated embodiment, a distal end of the passage 75 is located onthe distal side of the luer connection with the proximal end of thepassage 75 being located on the proximal side of the luer connection.

The one or more passages may be sized to filter blood or other liquid ormay include a filter or other structure that inhibits the passage of aliquid while allowing the passage of air. For example, the sheath itselfmay include one or more passages in the form of small openings, pores orporous material. Depending on the size of the one or more passages andthe expected size of the fluid molecules and formed elements (e.g. redblood cells), the one or more small openings, pores or porous materialin the sheath can form a porous vent that allows air to pass yet retainblood.

A method of manufacturing a ridged dilator will now be described. First,an extrusion process is used to create a long tubular body having one ormore longitudinal grooves or channels on its outer diameter (OD) orwithin the substance of the dilator. The long tubular body exceeds therequired length of a single dilator and preferably has a length that ismany times greater than the length of a single dilator. A manufacturingdie is employed in the extrusion process having geometry that reflectsthe desired geometry for the inside and outside diameters of the dilatorand the thickness and circumferential span of the longitudinal groovesor channels or interior channels. In the illustrated embodiment of FIGS.1-11, the long tubular body includes two longitudinal OD channels onopposite sides of the body to enhance the balance of the dilator withinthe sheath. However, a single channel can provide a visible indicatorfor the blood flash. The two channels preferably extend along the lengthof the extruded tubular body. While the illustrated embodiment includesone or more channel disposed between the dilator and the sheath, one ormore channels can in addition or in the alternative be formed betweenthe needle and the dilator, within the dilator, and/or within thesheath. In some embodiments, the dilator 24 thus is made partially orcompletely from clear, translucent, transparent, or semi-opaque materialto visualize the fluid flash within the channel.

With reference back to the illustrated embodiment, the extruded tubularbody is cut to the appropriate length for a single dilator. In thepreferred method, the two OD grooves extend for the entire length of thecut dilator.

A tipping process is then employed on an end of the cut dilator toreform the tip. An end of the cut dilator is forced into a die/mandrelhaving geometry that matches the desired geometry of the tip of thefinished dilator. The desired geometry is selected depending on, forexample, the inside diameter of the sheath. It is desirable for thesheath and dilator to form a close fit or seal near the tip to promoteblood flow in the proximal direction up the channel formed between thegrooved dilator and sheath. Preferably, the OD of the dilator in the tipregion tapers in the distal direction.

When in the die/mandrel, thermal energy is applied to the tip to reformthe tip to match the die/mandrel. The thermal energy may be applied byany known technique, including using radiant heating from an infrared orRF heat source. As part of the tipping process, the dilator in the tipregion is reformed so that the grooves are essentially removed. With thegrooves removed, the dilator is able to form the close fit or seal withthe sheath near the tip. The grooves are maintained along the remainderof the dilator on the proximal side of the location where the tip of thesheath 26 sits on the dilator. After removal from the die/mandrel, thetip end of the dilator may be cleaned and cut as necessary to remove anymanufacturing remnants.

The one or more fenestrations in the dilator is cut through the dilatornear the tip region and in or near the groove. Each fenestration may becut by any known means, including a drill or laser. Further, the cuttingdevice may be moved with respect to the dilator or vice versa to achievean oblong or other shape for the fenestration.

The end of the dilator opposite from the tip end can be flared tofacilitate over molding the dilator hub onto the dilator.

FIG. 4A is a plan view of the sheath 26 of the embodiment depicted inFIG. 1A. FIG. 4B is a cross-sectional view of the sheath 26 of theembodiment depicted in FIG. 4A, taken along line 4B-4B. FIG. 4C is anenlarged proximal end view of the sheath 26 of FIG. 4A. FIG. 4D is anenlarged perspective view of the sheath hub 42 of the sheath 26 of FIG.4A. As shown in FIGS. 4A-4D, the sheath 26 may comprise a sheath body40, a sheath hub 42, a distal portion 90, and a proximal region 92. Thesheath body 40 may be made partially or completely from clear,translucent, transparent, or semi-opaque material. The sheath body 40can also include one or more radio opaque markers, such as, for example,barium sulfate stripes. In a preferred embodiment, the sheath includestwo such radio opaque stripes disposed on diametrically opposite sidesof the body 40.

The sheath body 40 may be a single piece sheath through which a catheteror other medical article (e.g., a guidewire) is inserted into thevessel. In such an embodiment, the sheath body 40 forms a conduit forinsertion of the catheter or other medical article (e.g., a guidewire).In addition to providing a conduit, the sheath or a portion of thesheath can form a lumen that is in addition to the lumen(s) of thecatheter. For example, an equivalent to a triple lumen catheter can beformed by inserting a dual lumen catheter through the sheath body 40with the sheath body 40 itself forming a third lumen.

It may be advantageous to remove a portion or the entire sheath body 40depending on the type of catheter or medical article that is to beinserted into the vessel after employing the access device 20. Forexample, after the catheter or other medical article is inserted intothe vessel, a portion of the sheath body 40 can be separated orpeeled-away and removed. A peel-away sheath can include perforations,serrations, skives, or other structures, or include other materials(e.g., PTFE with bismuth) to allow the physician or healthcare providerto remove easily a portion or the entire sheath body 40.

The sheath hub 42 may include a luer slip connection and a lock member94. The locking member 94 may comprise a locking or attaching structurethat mates or engages with a corresponding structure. For example, thelock member 94 can be a luer connection 94 which can be configured toengage with the second luer connection 80 of the dilator hub 38.

The sheath hub 42, as best seen in FIGS. 4C and 4D, preferably isdesigned so that the locking mechanism or second luer connection 80 ofthe dilator hub 38 can enter the sheath hub 42 substantiallyunobstructed. However, in use, once the sheath hub 53 is placed at adesired location over the dilator shaft 36, the physician or healthcareprovider can push, pull, or twist the sheath hub 42 and possiblydisengage or engage the locking member 94 with a corresponding connectoron another medical article. The locking member 94 can be, for example, aluer connection, a protruding bump, dent, etc., that creates amechanical fit so that the dilator hub 38 and the sheath hub 42 arereleasably interlocked. In the illustrated embodiment, the lockingmember 94 of the sheath hub 42 comprises a luer connection. The sheathhub 42 preferably engages with the corresponding second luer connection80 on the dilator hub 38. Preferably, the locked position can bedisengaged or engaged by pulling, squeezing, pushing or twisting thedilator hub 38 relative to the sheath hub 42.

In some embodiments, the sheath hub 42 can comprise a lip 95. The lip 95can be threaded to allow the sheath hub 42 to attach to other medicalarticles with a corresponding locking feature.

The sheath hub 42 preferably comprises one or more surface features toallow the physician or healthcare provider to easily grasp or manipulatethe sheath 26 and/or access device 20. In the illustrated embodiment,the sheath hub 42 includes a squared grip 96 and ridges 98.

In additional embodiments, the sheath hub 42 may comprise radiallyextending wings or handle structures to allow for easy release andremoval of the sheath body 40 from other parts of the access device 20.In some applications, the wings are sized to provide the healthcareprovider with leverage for breaking apart the sheath hub 42. Forexample, the sheath hub 42 may comprise a thin membrane connecting thehalves of the sheath hub 42. The membrane is sized to keep the halves ofthe sheath hub 42 together until the healthcare provider decides toremove the sheath hub 42 from the access device. The healthcare providermanipulates the wings to break the membrane and separate the sheath hub42 into removable halves.

FIG. 5A is a perspective view of the guidewire section 28 of theembodiment depicted in FIG. 1A. FIG. 5B is a plan view of the guidewiresection 28 depicted in FIG. 5A, which preferably includes the guidewirehub 46. The guidewire hub 46 can comprise one or more surface featuresto allow the physician or healthcare provider to easily grasp ormanipulate the guidewire hub 46 and/or access device 20. In theillustrated embodiment, the guidewire hub 46 comprises one or moreridges 110. In a pre-loaded state, the outer surface of the guidewirehub 46 engages with a locking mechanism 130 on the track 30 when theguidewire hub 46 is in a third position 125 (example third positionillustrated in FIG. 6A).

In some embodiments, the guidewire 44 may form a close fit with theinside diameter of the needle body so as to provide a self-aspiratingfunction when retracted. For example, an outside diameter of theguidewire 44 may be selected to form a close fit with the needle alongthe length of the guide wire or along only a portion of the guidewire44.

In some embodiments, the distal end portion of the guidewire can have areduced diameter in comparison to other sections of the guidewire. Thesize of such reduced diameter section can be selected to permit fluid topass to the fenestration 56 in the needle body even when the guidewirehas been advanced beyond the distal tip of the needle.

FIG. 6A is a perspective view of the track 30 of the embodiment depictedin FIG. 1A. FIG. 6B is a plan view of the track 30 illustrated in FIG.6A. FIG. 6C is a side view of the track 30 illustrated in FIG. 6A. Asshown in FIGS. 6A-6C, the track 30 in the illustrated embodimentcomprises a distal portion 120, a proximal portion 122, a distal lockingmember 124 that connects the track to the dilator hub 38, a lockingmechanism 128 that inhibits further proximal and distal movement of theneedle hub 34 once the needle hub 34 is slid from the first position 121to the second position 123 along the track 30, and a locking mechanism130 that allows the guidewire hub 46 to attach to the track 30 when theguidewire hub is in the pre-loaded state or third position 125.Preferably, the track is made of polycarbonate material; however, asexplained below, other materials can be used.

The track 30 may further include a track section 132 of reduced width asshown most clearly in FIGS. 6A and 6B. The reduced width facilitatesassembly of the needle hub to the track 30. The illustrated embodimentincludes a rib 133 on the distal portion 120 of the track 30. The rib133 provides additional structural reinforcement between the distallocking member 124 and the remainder of the track 30.

As illustrated in FIG. 1A, the distal locking member 124 connects to thedilator 24 and allows the track 30 to extend proximally from the dilator24. For example, the locking member 124 can comprise two curved arms 124that connect to the dilator hub 38 between the dilator hub lip 77 andthe dilator hub base 79. The locking member 124 limits movement of thetrack 30 in a distal or proximal direction relative to the dilator hub38 but allows the track 30 to rotate freely around the dilator hub 38.

FIG. 6D is an enlarged view of a portion of the embodiment depicted inFIG. 6B. As shown, the locking mechanism 128 is formed by varying thewidth of the track in the region of the second position 123. Forexample, the illustrated embodiment includes a track section 134 ofincreasing width in the distal direction, a track section 136 of reducedwidth distal to the track section 134 of increasing width, and twofinger elements 138. The two finger elements 138 project from the distalend of the track section 136 toward the proximal end of the track 30 andflare away from the longitudinal axis of the track 30.

FIG. 6E is an enlarged view of a portion of the embodiment depicted inFIG. 6B. The locking mechanism 130 is formed by a clip, clasp or otherstructure that engages with a portion of the guidewire hub or with aportion of the track 30 when the guidewire hub is in the third position.Some or all of the engagement structure may be part of the track 30, bepart of the guidewire hub, or be split between the track 30 andguidewire hub. In the illustrated embodiment, the locking mechanism 130extends from the track 30 and engages with the guidewire hub. Thelocking mechanism 130 comprises a rectangular element 140 protrudingfrom the track 30, two track arms 142 projecting from the track 30distal to the rectangular element 140, and a stop 144 protruding fromthe track 30 distal to the track arms 142.

In the illustrated embodiment, the locking mechanism between the needlehub and the dilator resides on the proximal side of the dilator hub. Inother embodiments, however, the locking mechanism can be disposed atother locations as well. For example, where the locking mechanismincludes two pivotal levers which are joined by a locking hinge, thelocking mechanism can be disposed radially relative to the needle hub.In such an embodiment, one lever is pivotally coupled to the dilator andthe other lever is pivotally coupled to the needle. When the needle hubis moved away from the dilator hub, the levers straighten to a pointwhere the hinge locks. A similar effect can be obtained by a tetherlimiting proximal movement of the needle hub relative to the dilatorbeyond a particular point, thereby locking the components together. In afurther embodiment, an elongated structure can extend parallel to theneedle body from the needle hub within the dilator. Once the needle hubis moved a sufficient distance away from the dilator, additionalstructure of the locking mechanism (e.g., a detent) engages theelongated structure to inhibit further movement of the needle relativeto the dilator. Accordingly, as illustrated by these additionalembodiments, the locking mechanism operating between the needle and thedilator can be disposed at a variety of locations relative to thedilator hub.

FIG. 7A is an enlarged plan view of the access device of the embodimentdepicted in FIG. 1A pre-loaded with the guidewire. FIG. 7B is a sideview of the embodiment depicted in FIG. 7A. FIG. 7C is a cross-sectionalview of the embodiment depicted in FIG. 7A along line 7C-7C. FIG. 7D isa proximal end view of the access device 20 of FIG. 7A. In thispre-loaded state, the guidewire hub 46 is locked to the track 30 whenthe guidewire hub 46 is located in a third position 125. In thisposition, the guidewire hub 46 can be secured to the track 30 betweenthe rectangular element 140 and the stop 144. For example, the guidewirehub 46 can releasably lock between the rectangular element 140 and thestop 144. In addition, the track arms 142 can further secure theguidewire hub 46 to the track 30. This locking mechanism can arrestunintended rotational and axial movement of the guidewire 44 at least inthe distal direction when the guidewire hub 46 is in the third position125. Of course, the healthcare provider may disengage the guidewire hub46 from the track 30 to allow distal movement of the guidewire throughthe access device 20.

In the preloaded-state illustrated in FIGS. 7A-7C, the needle hub 34 islocked to the dilator hub 38 when the needle hub 34 is in the firstposition 121. Preferably, in the locked position, the openings orfenestrations in the needle and dilator are in register or in alignmentwith each other. When locked, the needle 22 and the dilator 24 areinhibited from at least unintentional rotational and axial movementrelative to each other. By preventing unintentional rotation of thedilator hub with respect to the needle 34, the fenestrations or openingsmaintain their general alignment.

In the pre-loaded state, the dilator hub 38 is secured to the sheath hub42. This can inhibit at least unintentional rotational and axialmovement between the dilator 24 and the sheath 26. In embodiments wherethe sheath hub 42 and the dilator 24 have only a luer slip connection,the dilator 24 and sheath hub 42 may rotate relative to each other.

FIG. 8A is a plan view of the embodiment depicted in FIG. 1A thatillustrates an operational step of one method of using the access device20. FIG. 8A depicts the needle body 32 of the access device 20 insertedinto a vessel 148, such as a vein. While the described method refers tovascular access, the access device 20 also can be used to access andplace a catheter or sheath into other locations within a patient's body(e.g., for draining an abscess) and for other purposes.

FIG. 8B is an enlarged plan view of the portion of the embodimentillustrated in FIG. 8A which is circled by line 8B-8B. FIG. 8C is anenlarged plan view of the portion of the embodiment illustrated in FIG.8B which is circled by line 8C-8C. FIG. 8D is an enlargedcross-sectional view of the embodiment depicted in FIG. 8C along line8D-8D.

As noted above, the needle body 32 comprises one or more side openings56 in its side wall. The dilator shaft 36 comprises one or more sideopenings 74. The side openings 56, 74 may have the same or differentshapes as well as aspect ratios. In the illustrated embodiment, the sideopening 56 in the needle body 32 has a different aspect ratio than theside opening 74 in the dilator shaft 36. The side opening 56 in theneedle body 32 is elongated in one direction (e.g., substantiallyparallel to the longitudinal axis of the needle body 32). The sideopening 74 in the dilator shaft 36 is elongated in a different direction(e.g., along the circumference of the dilator shaft 36). Having offsetelongated openings 56, 74 in the needle body 32 and the dilator shaft 36increases the likelihood that the openings 56, 74 in the needle body 32and dilator shaft 36 will be sufficiently aligned so that blood flowsthrough the needle side opening 56 and dilator side opening 74. FIGS.8A-D illustrate the alignment between only one set of corresponding sideopenings. Other sets of side openings can also be aligned or bemisaligned depending upon the relative orientations of the needle body32 and the dilator shaft 36.

In the illustrated embodiment, the dilator shaft 36 is coaxiallypositioned to minimize an annular space 150 between the needle body 32and the dilator shaft 36. The inner surface 152 of the dilator shaft 36need not, though it can, lie directly against the outer-surface 154 ofthe needle body 32. Preferably, in this embodiment, the annular space150 between the outer-surface 154 of the needle body 32 and the innersurface 152 of the dilator shaft 36 is minimized to inhibit the flow ofblood or its constituents (or other bodily fluids) into the annularspace 150 between the dilator shaft 36 and needle body 32.Advantageously, this feature minimizes the blood's exposure to multipleexternal surfaces and reduces the risk of contamination, infection, andclotting.

As illustrated in FIG. 8A, the dilator shaft 36 is coaxially mounted tothe needle body 32 such that at least part of one side opening 56disposed on the needle body 32 is rotationally aligned with at leastpart of one side opening 74 on the dilator shaft 36. Preferably, theneedle body 32 and dilator shaft 36 maintain rotational alignment sothat blood flows through the needle side opening 56 and dilator sideopening 74.

The sheath body 40, as noted previously, is preferably made partially orcompletely from clear, semi-opaque, translucent, or transparent materialso that when blood flows into the needle body 32, (1) through the needleside opening 56, (2) through the dilator side opening 74, and (3) into achannel 156, the physician or healthcare provider can see the blood. Insome modes, the channel 156 is formed between the dilator shaft 36 andthe sheath body 40 and defined by one or more ridges 76 on the dilatorshaft 36. In some modes, the channel 156 is formed within a wall of thedilator shaft 36 with the dilator shaft 36 preferably comprising atransparent material. Blood will indicate to the physician or healthcareprovider that the bevel tip 54 of the needle body 32 has punctured avessel 148.

In some embodiments, the needle body 32 and dilator shaft 36 may (both)have multiple side openings where some or all of these side openings canbe rotationally aligned.

The channel 156 can have an axial length that is almost coextensive withthe length of the sheath 26. In other embodiments, the channel 156 canbe significantly smaller than the elongated channel 156 just described.For example, but without limitation, the channel 156 can be disposedwithin a distal, mid and/or proximal portion(s) of the sheath 26. Thechannel 156 alternatively can have a linear, curved or spiral shapealong an axial length of the sheath 26 or can be formed by a pluralityof such shapes. The channel 156 may have various thicknesses and spanangles. The thickness of the channel 156 can range from almost close tozero to 0.010 inches. Preferably, the channel 156 has a thickness ofabout 0.0005 to about 0.003 inches. More preferably, the channel 156 canhave a thickness of about 0.001 inches to about 0.002 inches. Thechannel 156 can have a span angle Φ about the axis of the dilator 24 ofabout 30 degrees to about 210 degrees or more, but preferably less than360 degrees. More preferably, the channel 156 can have a span angle Φ ofabout 60 to 150. In the illustrated embodiment, the channel 156 spans120 degrees. The thickness and span angle Φ can be chosen so as tooptimize the capillary action that occurs within the channel 156 asfluid (e.g., whole blood) enters the channel 156 as may further beselected based on the expected pressure in the body cavity and viscosityof the liquid.

FIGS. 8E-8G are graphs of test data illustrating how quickly a fluid isdrawn up the surfaces of the channel 156 when the span angle is 120degrees, the contact angle (θ) is 5 degrees, and the circumferentiallength (H) is 0.64 mm at 60 degrees. On each graph, the filling length(mm) is plotted on the y-axis, and time (seconds) is plotted on thex-axis. The tests were performed at hydrodynamic pressures similar topressures experienced in peripheral vessels. FIG. 8E illustrates therate fluid is drawn up a channel 156 with a gap height width of 0.002inches, FIG. 8F illustrates the rate fluid is drawn up a channel 156with a gap height width of 0.001 inches, and FIG. 8G illustrates therate fluid is drawn up a channel 156 with a gap height width of 0.0005inches. As shown in FIGS. 8E-G, fluid is drawn up the fastest in achannel with a gap height width of 0.0005 inches, followed by a channelwith a gap height width of 0.001 inches, followed by a channel with agap height width of 0.002 inches.

The shape of the channel 156 described above and the resulting capillaryaction was optimized for use with whole blood as opposed to other fluidshaving a different viscosity than whole blood (e.g. leukocytes, pus,urine, plasma). However, the shape of the channel 156 is not limited tothe disclosed shape and may be optimized for draining other liquids,such as pus. Further, the shape of the channel 156 described above wasoptimized for peripherally located vessels where the pressure in thevessel enhances the capillary action and resulting blood flash as wellas for vessels located in the regions where the pressure may be low. Forexample, in the thorax region of the body, the expected pressure in theveins may be lower than in a peripherally located vein when the patientbreathes. A different size of the channel for use of the access device20 in other regions of the body may be employed taking into account theexpected pressure within the vessel or body cavity.

Additionally, an outer-surface 160 of the dilator shaft 36 and/or aninner surface 158 of the sheath body 40 can be coated with a substanceto promote or enhance the capillary action within the channel 156. Forexample a hydrophilic substance can be used to coat outer-surface 160 ofthe dilator shaft 36 and/or the inner surface 158 of the sheath body 40to enhance capillary action. As another example, a surfactant can beused to coat the outer-surface 160 of the dilator shaft 36 and the innersurface 158 of the sheath body 40. One example of a surfactant that canbe used is Lutrol 68™, commercially available from BASF™; othersurfactants can also be used. Other surfaces that can be coated includethe inner surface of the needle body 32, the outer surface 154 of theneedle body 32, the inner surface 152 of the dilator shaft 36, and theguidewire 44. These surfaces, including the outer-surface 160 of thedilator shaft 36 and the inner surface 158 of the sheath body 40, can becoated with a surfactant individually, or in combination. In theembodiments described above it may be preferable to coat both theouter-surface 160 of the dilator shaft 36 and the inner surface 158 ofthe sheath body 40 to promote or enhance progression of a body fluidthrough the channel 156. However, in some embodiments it may bepreferable to only coat one of these two surfaces with a surfactant.

Use of a surfactant can accelerate and facilitate the progression ofblood through the needle, dilator, or sheath. Accordingly, smallerneedles, dilators, and sheaths can be used while still allowing blood totravel through said pieces with sufficient speed to indicate to anoperator that the needle has entered the vessel or drainage site.Notably, in most embodiments a body fluid will pass through the needle,and thus in most embodiments it can be desirable to apply a surfactantto the interior surface of the needle.

Similarly, one or more of these components can be made of a hydrophilicmaterial. A hydrophilic substance additionally can be applied to theouter surface of the sheath 26 to act as a lubricant to ease insertionof the sheath 26 into a patient. Other lubricants or lubricous coatingscan be used on the exterior of the sheath 26 or at least the outersurface of the sheath can be formed of a lubricous material.Additionally, the sheath 26 can be coated or formed with agents (e.g.,heparin), which elute from the sheath, to facilitate the clinicalapplication of the access device 20. In one example, the outer surfaceof the sheath 26 can include a coating of silicone, such as Dow Corning360 Medical Fluid, 12,5000 CST™, commercially available from DowCorning. Similarly, the sheath can be coated with a surfactant in someembodiments.

FIG. 8H is a cross sectional view of the embodiment depicted in FIG. 8Calong line 8H-8H. In this region of the illustrated access device 20,the sheath body 40 is coaxially positioned to minimize the annular space157 between the sheath body 40 and the dilator shaft 36 while stillallowing relative movement of the sheath body 40 and the dilator shaft36. The inner surface 158 of the sheath body 40 need not, though it can,lie directly against the outer-surface 160 of the dilator shaft 36. Theannular interface 157 between the outer-surface 160 of the dilator shaft36 and the inner surface 158 of the sheath body 40 may be reduced inthis region to inhibit the distal flow of blood or its constituents (orother bodily fluids) from the opening 74 in the dilator shaft 36.

FIG. 8I is an enlarged plan view of the portion of the embodimentillustrated in FIG. 8A which is circled by line 8I-8I. FIG. 8J is across-sectional view of the embodiment depicted in FIG. 8I. FIGS. 8I and8J illustrate the needle hub 34 locked to the dilator hub 38 when theneedle hub is in the first position 121. The dilator shaft 36 may becoaxially mounted to the needle body 32 by slipping a hollow section 84of the dilator shaft 36 over the needle body 32 and releasably securingthe dilator hub 38 to the needle hub 34. The proximal end 86 of thedilator hub 38 is configured to mechanically fit and interlock with theneedle hub 34.

The dilator shaft 36 may be releasably mounted to the needle body 32 sothat the dilator shaft 36 can be mounted and released, or vice versa,from a coaxial position relative to the needle body 32. This lockingmechanism can inhibit at least some unintentional rotational and axialmovement between the needle 22 and the dilator 24 when the needle hub 34is in the first position. As shown, the needle hub 34 may have a luerconnection 64 that locks to the luer connection 78 of the dilator hub38. Furthermore, the needle hub 34 may also have latch element 66 thatlocks to the opening 82 in the dilator hub 38.

In addition, FIGS. 8I and 8J illustrate the dilator hub 38 engaged withthe sheath hub 42 when the access device 20 is inserted into a vessel148. Preferably, the proximal end 86 of the sheath hub 42 is configuredto mechanically fit and releasably engaged with the dilator hub 38. Asshown, the luer connection 80 in the dilator hub 38 can engage with thelock member 94 of the sheath hub. The resulting friction fit can inhibitat least some unintentional rotational and axial movement between thedilator 24 and the sheath 26 when the access device 20 is inserted intoa vessel 148.

FIG. 9A is a side view of the embodiment depicted in FIG. 1A thatillustrates a further operational step of the access device 20. FIG. 9Adepicts the guidewire 44 of the access device 20 advanced in a distaldirection into a vessel 148. This can be achieved by advancing guidewirehub 46 from the third position 125 in a distal direction. The guidewirehub 46 is then locked to the needle hub 34 when the needle hub 34 is inthe first position 121.

FIG. 9B is an enlarged side view of the portion of the embodimentillustrated in FIG. 9A which is circled by line 9B-9B. FIG. 9C is across-sectional view of the embodiment depicted in FIG. 9B. FIG. 9Cillustrates the locking mechanism between the guidewire hub 46 and theneedle hub 34. Preferably, the guidewire hub 46 is configured tomechanically fit and releasably or irreversibly interlock with theneedle hub 34. As shown, the guidewire hub 46 includes a nub 162 on theinner surface of the guidewire hub 46. The nub 162 of the guidewire hubcan lock onto the needle hub 34 by advancing the guidewire hub 46 in adistal direction until the nub 162 is secured within the threaded grooveon the lip of the needle hub 46. In other embodiments, the guidewire hub46 can lock to the needle hub 34 via corresponding threaded elements.

FIG. 10A is a side view of the embodiment depicted in FIG. 1A thatillustrates another operational step of the access device 20. FIG. 10Adepicts the dilator shaft 36 and the sheath body 40 advanced in a distaldirection into a vessel 148. This can be achieved by releasing thedilator hub 38 from the needle hub 34 and advancing the dilator 24 andsheath 26 in a distal direction relative to the needle hub 34 along theguidewire and needle. FIG. 10A further illustrates the proximal movementof the needle 22 and guidewire section 28 relative to the dilator 24 andthe sheath 26. The needle hub 34 will lock to the track 30 when theneedle hub 36 reaches the second position 123.

FIG. 10B is an enlarged rear view of the portion of the embodimentillustrated in FIG. 10A which is circled by line 10B-10B. As depicted inFIG. 10B, the needle hub 34 locks onto the track 30 via the lockingmechanism 128 in the second position 123. The needle hub tangs 68 slidein a proximal direction over the track fingers 138 and the tangs 68 canlock into place between the track fingers 138 and the track section ofincreasing width 134. This arrests and, more preferably, substantiallyirreversibly prevent axial movement of the needle body 32 at least inthe distal direction when the needle hub 34 is in the second position123. In the illustrated embodiment, the locking mechanism 128irreversibly prevents the needle hub 34 from moving in either theproximal or distal directions once engaged. Furthermore, the distal tip54 of the needle 22 is drawn into the dilator 24 to sheath the distaltip 54 when the needle hub 34 is in the second position 123. Thus, thislocking mechanism 128 inhibits the bevel tip 54 disposed on the distalportion 50 of the needle body 32 from being advanced beyond the distalend of the dilator shaft 36 once the dilator shaft 36 has been advancedover the needle body 32 during use. The dilator shaft 36 thus sheathsthe sharp bevel tip 54 of the needle body 32 to inhibit accidentalneedle sticks from occurring.

FIG. 11A is a side view of the embodiment depicted in FIG. 1A thatillustrates the final operational step of the access device 20. FIG. 11Aillustrates the removal of the guidewire 44 and the dilator shaft 36from the vessel leaving the sheath body 40 properly inserted within thevessel 148. FIG. 11B is an enlarged plan view of the portion of theembodiment illustrated in FIG. 11A which is circled by line 11B-11B. Asclearly shown in FIG. 11B, the distal end of the dilator shaft 36 andthe guidewire 44 extend beyond the sharp bevel tip 54 of the needle body32 to inhibit accidental needle sticks from occurring.

As noted above, having openings 56, 74 in the needle body 32 and dilatorshaft 36 with different aspect ratios will increase the likelihood thatthe openings 56, 74 in the needle body 32 and dilator shaft 36 will bealigned so that blood flows substantially unobstructed through theneedle side opening 56 and dilator side opening 74.

In the following embodiments, structure from one embodiment that issimilar to structure from another embodiment share the same rootreference number with each embodiment including a unique suffix letter(32, 32A, 32B, etc.). FIG. 12A is a plan view of another embodiment ofthe openings 56, 74 in the needle body 32 and dilator shaft 36illustrated in FIGS. 8B and 8C. FIG. 12B is an enlarged cross-sectionalview of the embodiment depicted in FIG. 12A along line 12B-12B. FIGS.12A and 12B depict a needle body 32A with an oblong opening 56A and adilator shaft 36A with a circular opening 74A. In other embodiments, theneedle can have a circular opening and the dilator can have an oblongopening. These embodiments can increase the likelihood that the openings56A, 74A will be at least substantially aligned so that blood flowsthrough the needle side opening 56A and dilator side opening 74A.

FIG. 13A is a plan view of another embodiment of the openings 56, 74 inthe needle body 32 and dilator shaft 36 illustrated in FIGS. 8B and 8C.FIG. 13B is an enlarged cross-sectional view of the embodiment depictedin FIG. 13A along line 13B-13B. FIGS. 13A and 13B depict a needle body32B with a circular opening 56B and a dilator shaft 36B with a circularopening 74B that is larger than the circular opening 56B in the needlebody 32B. In other embodiments, the opening in the dilator can besmaller than the opening in the needle. These embodiments can alsoincrease the likelihood that the openings 56B, 74B will be at leastsubstantially aligned so that blood flows through the needle sideopening 56B and dilator side opening 74B.

As noted above, the dilator shaft 36 may have one or more channels 156formed between ridges 76 to form a conduit or flow path between thesheath body 40 and the dilator shaft 36 to enable the physician orhealth care provider to view the blood after the bevel tip 54 of theneedle body 32 has properly punctured a vessel or the channels may beformed without ridges but by extruding axial indentations of variouspossible configurations or by forming fully enclosed channels within thedilator shaft or body.

FIG. 14A is a plan view of another embodiment of the ridges 76 depictedin FIG. 8C. FIG. 14B is an enlarged cross-sectional view of anotherembodiment of the ridges 76 depicted in FIG. 8D. FIGS. 14A and 14Bdepict two ridges 76C on the inner surface 158C of the sheath body 40Cthat form at least one channel 156C between the sheath body 40C and thedilator shaft 36C.

FIG. 15A is a plan view of another embodiment of the ridges 76 depictedin FIG. 8C. FIG. 15B is an enlarged cross-sectional view of anotherembodiment of the ridges 76 depicted in FIG. 8D. FIGS. 15A and 15Bdepict two ridges 76D on the inner surface 158D of the sheath body 40Dand two ridges 76E on the outer surface 160D of the dilator shaft 36Dthat combine to form a channel 156D between the sheath body 40D and thedilator shaft 36D. For example, if the desired channel thickness isabout 0.001 inches, the two ridges 76D on the inner surface 158D of thesheath body 40D can each be about 0.0005 inches thick and the two ridges76E on the outer surface 160D of the dilator shaft 36D can each be about0.0005 inches thick.

FIG. 16A is a plan view of another embodiment of the ridges 76 depictedin FIG. 8C. FIG. 16B is an enlarged cross-sectional view of anotherembodiment of the ridges 76 depicted in FIG. 8D. FIGS. 16A and 16Bdepict many ridges on the outer surface 160E of the dilator shaft 36E.Between adjacent ridges are splines 76F. The splines 76F form aplurality of channels 156E between the sheath body 40E and the dilatorshaft 36E. One or more of the channels 156E can have the same span angleΦ or different span angles Φ. In the illustrated embodiment the channels156E have span angles of 120 degrees and 23 degrees. In anotherembodiment, a single ridge 76 can spiral around the exterior of thedilator along its length.

FIG. 17 is an enlarged cross-sectional view through another embodimentof the access device and shows the channel 156F formed between a medicalarticle or sheath body 40F and a dilator shaft 36F that have dissimilarshapes. In the illustrated embodiment, the outer surface of the dilatorshaft 36F has an oval shape while the inner surface of the sheath body40F has a round shape. The oval dilator shaft 36F and the adjacent roundsheath body 40F form one or more channels or gaps 156F between thesheath body 40F and the dilator shaft 36F. Of course the shapes of thesheath body 40F and dilator shaft 36F are not limited to round and ovaland may include any other combination of dissimilar shapes in adjacentregions of the sheath body 40F and dilator shaft 36F. In some modes, theouter surface of the dilator shaft 36F is oblong and the inner surfaceof the sheath body or medical article 40F is round. In some modes, theouter surface of the dilator shaft 36F is round and the inner surface ofthe medical article 40F is square. The gap or channel 156F can follow alongitudinal axis, a spiral path along the longitudinal axis, a linearpath along the longitudinal axis or other path along the access device.In some modes, the linear path is parallel to the longitudinal axis. Thegap or channel 156F thickness can vary along at least a portion of alength of the gap or channel 156F.

In another mode, the access device includes a blood flash-back spacedefined between the shaft of the needle and the shaft of the dilator. Inthis mode, the flash-back space preferably vents to the atmosphere andmore preferably vents independent of the sheath. In particular, asdescribed below, a vent passage is formed through the dilator, throughthe needle, or between the dilator and the needle.

FIGS. 18A-18E illustrate an embodiment of this mode of the accessdevice, wherein a vent channel is formed between the needle and thedilator. As best seen in FIGS. 18A-18C, the needle body 32G includes oneor more fenestrations 56 (e.g., like any of the fenestrations depictedin FIGS. 12A-16A), and one or more optional ridges 176 (e.g., two ridges176 are shown in the illustrated embodiment). The ridges 176 define thesides of at least one channel 256 extending along a length of the needlebody 32G. In some embodiments additional channels 256 can be formed withadditional ridges. In other embodiments channels 256 can be formed witha protruding ridge, or without a protruding ridge such as with adepression(s) or with a concentric gap. Similarly, a channel 256 can beformed with protruding or non-protruding ridges on the inner surface ofthe dilator shaft 36G (instead of or in addition to features on theneedle body 32G). Although the channel 256 is depicted as straight, itcan also form other patterns such as a helix or another shape wrappingabout the access device. Further, where multiple channels are presentthey can form intersecting helices, parallel helices, or other patterns.In other embodiments, a distance between the needle body 32G and adilator shaft 36G (e.g. where the inner diameter of the dilator shaftexceeds the outer diameter of the needle body) can generally define aspace, or a generally annular space, similar to the space created by thechannels 256.

As best shown in FIG. 18D, the needle hub 34G can include one or moreventing grooves 175. As depicted, the venting grooves 175 are on theluer connection 64, but in other embodiments they can be located on theneedle body 32G, on the dilator shaft 36G, pass through the needle hub34G, pass through a dilator hub 38G, or take some other path. Theventing grooves 175 can provide communication between the channels 256(or similar spaces) and the ambient atmosphere. The luer connection 64can be configured to cooperate with the dilator hub 38G to form asubstantially liquid tight seal, such that a substance can only escapethrough the venting grooves 175. In embodiments where the ventinggrooves 175 do not extend radially, a generally radially extending side180 of the needle hub 34G can be configured to rest far enough apartfrom a corresponding face 200 of the dilator hub 38G to allow air topass between them, from the venting grooves 175.

In some embodiments, the venting grooves 175 can form a passagesufficiently small in cross-sectional area to allow the escape of gases(e.g., air) to the ambient atmosphere while hindering the escape to theambient atmosphere of body liquids (e.g., red blood cells) with highmolecular sizes, viscosities, or surface tensions. Further, in someembodiments multiple such passages can be provided, allowing adequateair ventilation despite small cross-sectional passages.

In other embodiments, the small cross-sectional area of the passage canbe provided between two opposing surfaces of the dilator hub 38G and theneedle hub 34G. For example, at least a portion of the venting groove175 on the needle hub 34G can be configured to receive a generallycorrespondingly shaped venting surface on the dilator hub 38G withoutentirely blocking the venting groove. The resulting passage between thesurfaces of the needle hub 34G and the dilator hub 38G thus define atleast a region of relatively small cross-sectional area to permit airflow but restrict the flow of bodily fluids.

While the venting structure is depicted as grooves 175 in theillustrated embodiment, other structures can perform similar functions.For example, a single reduced space location between the needle body 32Gand the dilator body 34G can permit the escape of air while inhibitingthe flow of blood proximally beyond the reduced space location.Similarly, a labyrinth passage can be disposed between the ambientatmosphere and the flash-back space (the space between the needle anddilator).

In other embodiments, one or more of the venting grooves 175 can befilled at least in part by a porous material that permits gases to flowthrough the material but inhibits the passage of a body fluid (e.g.,blood). Such material can be integrally formed into the needle hub 34Gor dilator hub 38G such that the material and the hubs are unitary. Thematerial can then comprise any portion of the length of the ventinggrooves 175. In other embodiments the material can be placed into theventing grooves 175 or a receptacle in communication with the groove(s).When the material is placed into the groove 175, the groove can includea receiving portion such as a groove notch 185 configured to receive theporous material. One or more of the vent passages in other embodimentscan be entirely formed by such porous material. Suitable porousmaterials include, but are not limited to a porous polymer such as HDPE,UHMWPE, PP, PTFE, PVDF, EVA, PE, Nylon, and PU, of pore sizeapproximately 2.5 microns. In further embodiments, a combination of porevolume and pore size can be chosen to allow passage of gases (such asair) but inhibit the passage of body fluids (such as blood).

In further embodiments, the venting passages can be tubes defined solelyby either the needle hub 34G or the dilator hub 38G. For example, thechannel 256 can lead to an opening in the needle hub 34G. This openingcan include any of the characteristics discussed above to control thepassage of gases and fluids. The opening can thus allow the escape ofgases (e.g. air) through the needle hub 34G to the ambient atmospherewhile inhibiting the passage of body fluids (e.g. blood). In otherembodiments, a similar venting passage can be a tube defined solely bythe dilator hub 38G. It will be clear from the disclosure herein that avariety of passages (e.g. venting grooves 175, tubes, porous material,etc.) can be used to allow the escape of gases (e.g. air) to the ambientatmosphere while inhibiting the escape of body fluids (e.g. blood).

In another embodiment, the venting passages can be within the dilatorshaft 36G and the sheath body 40. For example, a venting hole or a patchof venting material can be provided in each of the dilator shaft 36G andthe sheath body 40. In some embodiments these venting structures canoverlap, allowing gases to pass directly from one to the other. In otherembodiments, these venting structures can be positioned some distanceaway from each other, in which case a channel or groove similar to thosein FIG. 18D can be provided between the dilator shaft 36G and the sheathbody 40 to bring the venting structures into communication. Theseventing structures can be provided proximal from the fenestration 56 inthe needle body 32G.

As shown, the dilator shaft 36G in this embodiment can have nofenestration and can be generally continuous. The dilator shaft 36G canthus radially close the channel 256 (or similar space). In similarembodiments the same functionality can be accomplished with ridges inthe dilator shaft 36G cooperating with an otherwise generally continuousneedle 32G including a fenestration 56. The dilator shaft 36G can beformed of a translucent material in the entirety, or alternatively betranslucent in at least the region adjacent the channel 256. The sheathbody 40 can be similarly formed of a translucent material. In otherembodiments, the material can be transparent instead of onlytranslucent. In further embodiments, the material can be only partiallytranslucent both spatially and temporally. Spatially, the material ofthe dilator shaft 36G and/or the sheath body 40 can be translucent nearthe channel 256, allowing visual confirmation of e.g. blood flash-back.Temporally, the visual characteristics of the material can change uponentry of a body fluid (e.g. due to temperature change or molecularinteraction). The material can thus become translucent upon entry of abody fluid, or in other embodiments change color or provide some othervisual indication.

Further, the access device depicted in FIGS. 18A-18E can includesurfactants and/or lubricious coatings, as described above. For example,in some embodiments a surfactant can be applied to the interior of thedilator shaft 36G, the exterior of the needle 32G, and/or the interiorof the needle. The surfactant can be applied to any combination of thesesurfaces, depending on the desired effect. For example, the surfactantcan be applied solely to the outer surface of the needle, solely to theinner surface of the dilator, or solely to the inner surface of theneedle. As another example, a surfactant can be applied to combinationsof these surfaces, such as to both the inner surface of the dilator andthe outer surface of the needle. The surfactant can ease the passage ofa body fluid through spaces within the access device, acceleratingflashback. As another example, in some embodiments a similar channel canbe provided between a dilator shaft and a sheath body, and thesurfactant can be supplied on the inner surface of the sheath and theouter surface of the dilator. Even further, in some embodiments channelscan be provided both between the dilator and needle and the dilator andsheath, with the channels being in communication via a fenestration inthe dilator, as described herein. Further, as described above, the outersurface of the sheath can be coated with a surfactant, lubriciousmaterial, or the like.

In other embodiments, the channel 156 can be formed by having onecomplete ridge on the inner surface of the sheath and one complete ridgeon the outer surface of the dilator. In other embodiments, the innersurface of the sheath can have two ridges that run 50% of the length ofthe channel 156 and the outer surface of the dilator can have two ridgesthat run the remaining 50% of the channel 156.

In even further embodiments, the venting can be provided at leastpartially through an insert 451 between a dilator hub 438 and needle hub434, as best shown in FIGS. 19A, 19B. In some embodiments, an additionalpiece such as the insert 451 can facilitate the provision of certaindesirable dimensions, materials, and other design features that mightnot be otherwise possible or economical. For example, in the embodimentdiscussed above regarding FIGS. 18A-18E, it may be desirable for amiddle portion of the dilator shaft 436 to have an inner diametersubstantially larger than the outer diameter of the needle body 432 neara needle fenestration (such as those described in relation to otherembodiments). This difference in diameters can create a space thatallows a body fluid to flow between the two (such as in the channel 256)from the fenestration. However, as will be discussed further below, insome embodiments it may also be desirable to provide the dilator shaft436 with a smaller inner diameter near the dilator's distal tip. Infurther embodiments (such as those described above) it may be desirableto provide a proximal portion of the dilator 424 that also has a smallerdiameter to hinder the flow of a body fluid such as blood proximallywhile still allowing the venting of gases. As discussed above, thisventing can facilitate the drawing of a body fluid into the space,cavity, or channel. However, it may be difficult to manufacture adilator 424 with small inner diameters at its proximal and distal ends,and a large inner diameter in a middle portion.

The embodiment depicted in FIGS. 19A-19C provides venting with theassistance of an insert 451. The insert 451 can be disposed within aproximal opening 460 of the dilator hub 438. The proximal opening 460can be configured to also receive a distally protruding portion 461 ofthe needle hub 434, as described in similar embodiments above (e.g., theportions forming a luer fitting between the needle and dilator hubs). Insome embodiments the insert 451 can be press-fit into the dilator hub434, while in other embodiments it can be loosely slid onto the needlebody 432 (prior to combination with the dilator 424).

As best depicted in FIG. 19C, the insert 451 defines a through-hole 452that can slidingly receive the needle 422 (or another needle describedherein), e.g. along the needle body 432. Further, as depicted, theinsert 451 can be substantially circular, or donut-shaped, allowingflexibility in its rotational position within the dilator hub 438.However, in other embodiments the insert 451 can be rotationally fixedwithin the dilator hub 438, i.e., with a non-circular insert and acorresponding non-circular receiving portion in the dilator hub 438.

Even further, the insert 451 can have particular dimensions tofacilitate the release of gases while hindering the release of bodyfluids. For example, the diameter of the insert's through-hole 452 canbe only slightly greater than the outer diameter of the needle body 432,creating a space that allows the release of gases but hinders therelease of a body fluid. As best shown in FIGS. 19A, 19B, the gases canthen enter a space between the needle hub 434 and the insert 451 withinthe receiving portion of the dilator hub 438. From this space, the gasescan then proceed to the ambient atmosphere in a passage 462 definedbetween the needle hub 434 and the dilator hub 438. Notably, although insome embodiments the needle hub 434 and the dilator hub 438 can connectvia a luer connection that may prevent the passage of gases, additionalmechanisms can also attach the two hubs. For example, in the depictedembodiment the needle hub 434 can include a hook portion 470 that canreleasably hook to a ledge portion 471 of the dilator. In otherembodiments the latch element 66 and the opening 82 (described inprevious embodiments) can also attach the two hubs. Thus, componentsthat might otherwise form a luer connection between the two hubs canalso be sufficiently separated to allow the escape of gases withoutcompromising a connection between the hubs.

Further, the outer edge of the insert 451 can be shaped to substantiallymatch the receiving portion of the receiving portion of the dilator hub438 to form a seal between the two that at least hinders the escape of abody fluid therethrough. In some embodiments, a taper within the dilatorhub 438 (also used for a luer connection with a needle, as discussedabove) can facilitate a seal between the insert 451 and the dilator hub.In some embodiments, the seal between the outer edge of the insert 451and the receiving portion 460 of the dilator hub 438 can also beimpermeable to gases, forcing their passage through the through-hole452, as described above.

During assembly, when the insert 451 is inserted into the dilator hub438, the insert can sometimes enter slightly off-angle from thereceiving portion and thus be stuck slightly ajar. Due to the size ofthe pieces and the depth of the receiving portion 460, it may bedifficult to detect when the insert 451 is ajar. Thus, the insert 451can be configured to provide tolerances for such off-angle insertion.For example, as depicted the through-hole 452 can include aproximally-tapered portion 453. The proximally tapered portion 453 canhelp preserve a venting space between the needle body 432 and the insert451 through which gases can escape but the escape of a body fluid can behindered.

The insert 451 can also include a proximally projecting portion depictedas a ridge 455 along its proximal face, which can be of particularrelevance as shown in FIG. 19B. If the insert 451 is ajar, it may notcompletely enter the dilator hub 438, as depicted in FIG. 19B. Theinsert 451 can then come into contact with the needle hub 434. Suchcontact between the needle hub 434 and the insert 451 could thenpotentially form a seal, preventing the escape of gases through theinsert's through-hole 452. Thus, in some embodiments, the insert canalso include a ridge 455 with grooves 456. The needle hub 434 cancontact the ridge 455 before contacting the rest of the proximal end ofthe insert 451, preserving a space therebetween. Further, the ridge 455can include one or more grooves 456, providing an opening in the ridge455 for gases to pass through, to the passage 462 between the hubs 434,438. In the depicted embodiment, more than one groove can be provided toadvantageously allow gases to pass through in multiple directions. Thus,if sealing contact between the insert 451 and the needle hub 434 is madeon one side, gases can still escape on the other side.

In other embodiments, the proximally projecting portion on the insert451 can take other forms. For example, in some embodiments the insert451 can have one or more distinct projections to maintain separationfrom the needle hub 434. In further embodiments, the insert 451 caninclude one or more grooves that allow the escape of gases despitecontact with the needle hub 434. Even further, in some embodimentssimilar structures can be provided on the needle hub instead of or inaddition to the structures on the insert.

FIGS. 20A-20E depict another embodiment of a dilator 24H that includesadditional elements to enhance the fluid flash-back feature of theaccess device 20. One additional element involves at least one wiper orseal that interacts with a needle (e.g., the needle 22 described inconnection with the embodiment illustrated in FIGS. 1-7 above) aboutwhich the dilator 24H is coaxially disposed to inhibit fluid uptakethorough a space occurring between the needle exterior (e.g., needleexterior surface 154 of FIG. 8D) and the dilator interior (e.g., dilatorinterior surface 152 of FIG. 8D). The seal feature can be incorporatedinto any of the previously described embodiments of the access device20, along with or separate from the other elements depicted in FIGS.19A-19C. For example, the seal feature can have a smaller inner diameterand be on a dilator body associated with the dilator hub 438 depicted inFIGS. 19A-19C. While the illustrated embodiment describes thisadditional element in connection with a single seal, the dilator caninclude multiple seals located along the length of the dilator. Suchseals can be located in series to the proximal side of the dilatorfenestration and/or the needle fenestration. Additional seals can belocated on the distal side of such fenestration as well in someembodiments; however, in the illustrated embodiment, the seal isdepicted to the proximal side of both the dilator and needlefenestrations.

With reference to FIGS. 20B and 20C, the dilator 24H includes a sealingportion 250 that lies slightly proximal of a fenestration 74H on thedilator 24H. The sealing portion 250 is depicted as an inward protrusionthat creates a narrowed region in the interior of the dilator 24H. Atthis sealing portion 250, the dilator 24H can form a seal with a needle(not shown) to separate the space between the dilator 24H and the needleinto proximal and distal sections each lying to one side of the seal.One potential result is that, in embodiments where a fluid is intendedto advance from the needle bore to a space between the dilator 24H and asheath (e.g., the sheath 26 described in connection with the embodimentillustrated in FIGS. 1-7 above), fluid leakage into the proximal spacebetween the dilator 24H and the needle is reduced, as the body fluid isinhibited from passing proximally beyond the sealing portion 250.Further, in some embodiments the sealing portion 250 can serve as awiper, removing fluid (e.g., blood) from the surface of the distalportion of a needle as it is retracted into the dilator 24H.

The sealing portion 250 can take a variety of cross-sectional shapes,including triangular (an example of which is illustrated in FIG. 20C),rounded or rectangular. In the illustrated embodiment depicted in FIG.20C, the sealing portion 250 has a generally triangular cross-sectionalshape formed in part by a tapering surface 252 that slopes inwardpreferably in a proximal direction. The tapering surface 252 intersectswith a ledge 251 of the sealing portion 250. The ledge 251 liesgenerally perpendicular to a longitudinal axis of the dilator 24H;however, in other embodiments, the ledge 251 can lie at various anglesrelative to the longitudinal axis so that an angle formed between thetapering surface 252 and the ledge 251 can be acute, right or obtuse.Advantageously, the tapering surface 252 on the sealing portion 250 canassist movement of the needle through the dilator 24H in a proximaldirection. The ledge 251 allows the sealing portion 250 to deflectproximally as a needle is passing through. The dimension of the inwardprojection of the sealing portion 250 preferably is not significantlyless than, and is more preferably greater than half of the difference indiameters between the exterior of the needle and the interior of thedilator at the point of the fenestrations.

As further depicted in FIG. 20B, in some embodiments the dilator 24H caninclude an expanded portion 260, formed with a taper 262 proximal of thesealing portion 250. The expanded portion 260 can reduce contact andfriction between the dilator 24H and a needle (or other article for thatmatter) passing through the dilator 24H. When the sealing portion 250inhibits proximal passage of a body fluid, the proximal space within theexpanded portion 260 will receive little if not none of the body fluidacross the seal formed by sealing portion 250. Additionally, in someembodiments a needle or other article passing through the dilator 24Hcan include a stop portion extending axially outward to engage the taperand inhibit further advancement of the article. Thus, the expandedportion 260 and its coinciding taper can define a limit on axialmovement between the dilator 24H and a corresponding needle or otherarticle.

When the needle is withdrawn into the dilator and locked therein, thedistal end of the needle can lie to the proximal side of the sealingportion 250 in some embodiments, and can lie to the distal side of thesealing portion 250 in other embodiments. In either position, theabsence or the reduction of fluid on proximal side of the seal lessensthe amount of body fluid flowing through the dilator hub once thedilator has been withdrawn from the patient's body.

The sealing portion 250 can be formed on the dilator in any of a widevariety of ways readily known to those skilled in the art. For example,in some embodiments, the sealing portion 250 can be formed during adilator tipping process after the dilator has been extruded. An internalmandrel can be cut with an annular groove that has the inverse image ofthe sealing portion 250. The mandrel is then placed within dilator. Asthe material of the dilator's distal end is heated during the tippingprocess and then pressed into the desired exterior shape, the materialwill also be forced into the annular groove on the mandrel to form thesealing portion 250. After sufficient cooling, the dilator can bewithdrawn.

In other embodiments, a sealing portion can take a different form. Forexample, a needle can have an expanded exterior portion, forming anenlarged external diameter on the proximal side of its fenestration,similar to the enlarged internal diameter of the expanded portion 260 ofthe embodiment depicted in FIGS. 20A-20C. As such, the needle can have asmaller external diameter at a distal portion and a larger externaldiameter at a distal portion. The enlarged diameter portion can engageor abut against the internal surface of the dilator (e.g., against taper262) to form a sealing portion similar to that described above. In someembodiments, the contact between the needle and dilator, forming asealing portion, can be formed between matching tapers such as the taper262 on the dilator 24H and a similar external taper on the needle. Inother embodiments the contact between the needle and the dilator can beon other surfaces, such as surfaces generally parallel with thelongitudinal axis of the needle and dilator.

As additionally indicated in FIGS. 20A, 20B, the dilator 24H can have aninner diameter d1 in a portion distal from the fenestration 74H.Further, as indicated in FIG. 21B (further discussed below), a needle(such as the needle 22J, or other needles such as the needle 22) canhave an outer diameter d2. In some embodiments, d1 can be less than d2;this can provide a number of advantages. For example, the interferencefit of the dilator 24H on the needle can put the dilator 24H under aradial or hoop load. This loading can increase the strength of thedilator 24H in an axial direction. The increased strength tends toreduce flaring, crimping or buckling of the material at the distal tipof the dilator when inserting the dilator through tissue (e.g., skin,muscle and/or vascular wall). For example, as the needle and dilator 24Hpass through skin (without the use of a skin nick) the dilator canwithstand axial forces that may otherwise deform the distal tip of thedilator. In some embodiments, this could cause a dilator to bunch, fold,or curl upon itself, increasing its cross-sectional area at said bunchor fold and inhibiting its functionality as a dilator. In other words,the deformed dilator becomes too difficult to insert into the patient.Providing the dilator with a smaller inner diameter d1 can increase thestrength of the dilator, inhibiting the occurrence of such deformations.

In some embodiments, the inner diameter d1 of the dilator 24H can besmaller than the outer diameter d2 of a needle on which it mounts byapproximately 15% or less. In other words, the outer diameter d2 of theneedle can be approximately 15% larger than the inner diameter d1 of thedilator 24H. In more preferred embodiments, the inner diameter d1 of thedilator 24H is smaller than the outer diameter d2 by approximately 10%or less. In even more preferred embodiments, the inner diameter d1 issmaller than the outer diameter d2 by approximately 2% to 4% of theouter diameter d2. In particularly preferred embodiments, the innerdiameter d1 of the dilator 24H can be approximately 97% of the outerdiameter d2 of a needle on which it mounts.

Further, as depicted in FIG. 20B, the dilator tip can be beveled toprovide a smoother dilation and to ensure further that the dilator tipdoes not deform upon entrance into the patient's body. As indicated, thetip can have a taper or bevel at an angle φ on each side (it is notedthat the indicated angle φ's opposite angle is equal to φ, and thus theyare treated as the same herein). The beveled tip can reduce axial forceson the dilator 24H upon passage through tissue (e.g., skin). In someembodiments, the angle φ can be approximately 30 degrees. In otherembodiments, the angle φ can be between approximately 40 and 20 degrees.After this initial bevel, the dilator tip can taper at a shallowerangle, as depicted in FIG. 20D. For example, in some embodiments thedilator can then taper at approximately 3 degrees, or alternatively atan angle less than approximately 3 degrees.

Additionally, as depicted in FIG. 20E, the dilator 24H can include aridge or protrusion 264 through which the fenestration 74H passes. Thus,the ridge 264 can separate a sheath overlapping the dilator,facilitating any flow through the fenestrations 74H into a space betweenthe dilator 24H and said sheath. Further, as depicted the ridge 264 canbe generally thinner than the fenestration 74H. Thus, the ridge 264 cancontact and separate the sheath while also leaving space for a fluid toflow around the ridge. As depicted, the ridge 264 can be generallyoriented in an axial, proximal-distal direction. However, in otherembodiments the ridge 264 can be oriented in a circumferential directionor otherwise.

FIGS. 21A and 21B depict a further embodiment of a needle 22J that canbe used in a manner similar to that of other needles described hereinsuch as the needle 22. The needle 22J can comprise an echogenic portion270 at the distal tip. The echogenic portion can comprise a materialthat scatters waves used in imaging, thus facilitating visualization ofthe needle under ultrasound. Other imaging techniques can also be used,such as using a needle having a radio-opaque portion facilitatingvisualization under X-rays or fluoroscopy. The echogenicity can beincreased by sandblasting the portion 270 to roughen the surface. Thetip can be sharpened after sandblasting, allowing the tip of the needleto be echogenic. Echogenicity can also be increased by modifying theinternal material of the needle itself, such as by adding granularimpurities. However, in some instances modification of the internalmaterial may unacceptably compromise the structural integrity of theneedle. Advantageously, the echogenicity or similar imagingcompatibility can allow an operator to easily view the needle tip insidethe body using a scanning technique such as ultrasound.

In some embodiments a needle with an echogenic portion 270 can furtherlack fenestrations 56, 74, grooves 75, and/or surfactant. Further, insome embodiments with an echogenic portion 270, the access device canlack a flashback space or flash chamber.

In other embodiments, the needle 22J can have both an echogenic portion270 and a fenestration 56 (in addition to other optional featuresdescribed above). Further, in other embodiments, the needle 22J caninclude a contrast portion 280. The contrast portion 280 can haveoptical properties that improve the visibility of a fluid surroundingthe contrast portion. For example, as described above, in someembodiments a body fluid can flow into a flashback space through thefenestration 56. The contrast portion 280 can then be positionedgenerally adjacent the flashback space and the contrast portion can haveoptical properties that contrast with the body fluid. Thus, the bodyfluid's entry into the flashback space can be more immediately apparent.

For example, in embodiments where the fluid entering the flashback spaceis a body fluid such as blood, the contrast portion 280 can have a colorthat contrasts with the color of blood, such as white, green, blue, etc.In further embodiments, other optical properties can be varied such asby choosing between a reflective or matte finish. In other embodiments,the contrast portion 280 can have be striped, checkered, dotted, or havesome other pattern wherein the optical properties vary. For example, thecontrast portion 280 can have black and white stripes oriented axiallyand/or circumferentially along the needle. Where a pattern withdifferent optical properties is utilized, the contrast portion 280 canbe more generic to different fluids that may be distinguishable from oneregion of the contrast portion 280 but not another region.

The varying optical properties can be applied in a variety of ways. Forexample, in some embodiments the contrast portion 280 can be painted tohave a particular color, finish, pattern, etc. In other embodiments,portions of the needle can be polished or roughened to effect thereflective properties of the contrast portion 280. In even furtherembodiments, the contrast portion 280 can be formed from a differentmaterial, or have a different material applied to its surface, to yielddifferent optical properties. Even further, in some embodiments thecontrast portion 280 can be made echogenic, as in the echogenic portion270 described above.

As depicted in FIG. 21A, the contrast portion 280 can be positioned justproximal from the fenestration 56 and extend a distance less than theentire distance of the needle 22J. This position can generallycorrespond to the beginning of a flashback space that may also be justproximal of the fenestration 56. However, in other embodiments theposition of either or both the flashback space and the contrast portion280 can vary. For example, in some embodiments the contrast portion 280can span across the fenestration 56, or can be offset some distancetherefrom. In further embodiments, the contrast portion 280 can extendto the needle hub or can span the entire needle body. As depicted, thecontrast portion 280 can span circumferentially about the entire needle.However, in some embodiments the contrast portion 280 can be positionedonly along an angularly reduced portion of the needle body, such as anangular portion having an angular span corresponding to the angular spanof the fenestration 56.

In embodiments where the flashback space occurs between a dilator and asheath (as described above), the dilator can have corresponding portionsthat are clear, translucent, transparent, or semi-opaque, such that thecontrast portion 280 can be viewable from outside the access device.Then, as a fluid such as a body fluid enters the flashback space anobserver can see both the contrast portion 280 and the body fluid as itenters the flashback space to occlude the contrast portion 280. Thecontrast in optical properties between the fluid and the contrastportion 280 can then facilitate the visual detection of the fluid'sentry.

Additionally, in such embodiments where the flashback space occursbetween the dilator and the sheath, the flashback can be enhanced oraccelerated by sealing off or restricting air flow from the spacebetween the needle body and the dilator body. In a preferred embodiment,fluid leakage (e.g., air egress) between a dilator and sheath can bereduced by placing a sealing piece such as a washer between the needleand dilator hubs. The washer reduces any fluid flow that might occurbetween a dilator and needle at their abutting hubs. Thus, a trapped aircolumn can form between the dilator and needle that inhibits the flow ofa body fluid (e.g., blood) into the space between the needle anddilator. The body fluid flow can thus be diverted, e.g., into a dilatorfenestration 74H and into a space between a dilator and sheath. In someembodiments, the washer can be an elastic material, such as silicone.The washer can mount on the needle and have a planar or an o-ring-likeshape.

This concept can also be applied to other embodiments. For example, insome embodiments a flashback space can be provided between a needle anda dilator. As between the dilator and the sheath, as discussed above, achannel can be formed between the needle and the dilator that canreceive blood or other fluids through the needle fenestration 56. Anexample of such a flashback space is described in FIGS. 18B-18D and theaccompanying text in Application No. PCT/US2009/037204, filed 13 Mar.2009, and incorporated herein by reference in its entirety.

Thus, in some embodiments a preassembled access device can optionally beprovided with a needle 22J that does not include any fenestrations andthat can (but need not) be echogenic (depicted in FIGS. 21A, 21B), alongwith a guidewire, dilator, sheath, and associated hubs. Further, thepreassembled access device can be inserted inside packaging, in thepreassembled state. An operator can insert the access device into apatient and stop the advancement of the needle once the needle enters atargeted body space, as viewed from outside the body by ultrasound,X-ray, or some other imaging technique. The preloaded guidewire can thenpass through the needle into the body space. The dilator can be advancedover the needle into the body space. The needle can be withdrawn thepatient and further actions can be taken to insert the sheath over thedilator, as described above in relation to other embodiments.

In some embodiments, an access device can also include a modified track30K and guidewire hub 46K, as depicted in FIGS. 22A-23B. As depicted,the track 30K and guidewire hub 46K can be substantially similar to thetracks and hubs discussed above, can be operated in a similar manner,and can be used similarly with other elements such as the needles,dilators, and sheaths described herein. For example, the track 30K cangenerally define a third position 125K with some similarity to the thirdposition 125 described above. As depicted, the third position 125K caninclude a releasable coupling mechanism 130K that can engage with theguidewire hubs with corresponding parts, such as the guidewire hub 46K.The coupling mechanism 130K can include a coupling section 290 formedfrom a T-shaped projection extending from the track 30K. The T-shapedprojection can additionally include two latch recesses, on each side ofits base, generally toward a distal end of the coupling section 290.

A corresponding guidewire hub 46K can have corresponding structure withthe coupling section 290 to releasably connect thereto. As depicted, theguidewire hub 46K can include a receiving section 296 that can be in theform of a recess. The recess can have a T-shaped cross-section at aproximal end to match the coupling section 290, as best depicted in FIG.23A. Further within the recess of the receiving section 296, thereceiving section can receive the base of the coupling section 290 alongtwo tines that can terminate with latch projections 298. The latchprojections 298 can interact with the latch recesses 292 on the couplingsection 290 to form a reversible snap-fit between the track 30K and theguidewire hub 46K. In some embodiments, the tines can include bendingportions 302 (formed e.g. from thinned material, to facilitate thesnap-fit. Further, the receiving section 296 can include an end recess300 in-line with the provided path provided for the coupling section 290between the tines, such that when the latch recesses 292 and projections298 interengage, the coupling section 290 can also enter the end recess300. Thus, the connection between the track 30K and hub 46K can befurther stabilized.

Additionally, in the depicted embodiment of the track 30K, the track caninclude a grip projection 294. The grip projection 294 can extenddownward from the track 30K, opposite from the coupling section 290. Asdepicted, the grip projection 294 can be generally circular withgripping ridges, but other structures and shapes are possible.Advantageously, the grip projection 294 can allow an operator of theaccess device to hold the proximal end of the track 30K in a pistol-typegrip. For example, a ring finger or middle finger can be positionedaround the grip projection 294 to contact it on the distal side. Thethumb of the same hand can then be placed on the proximal end of aguidewire hub 46K coupled in the third position 125K. The thumb can theneasily apply pressure to move the hub 46K off of the coupling section290 and out of the third position 125K. A similar grip projection can beapplied to other tracks, such as the track 30 described above. Further,similar grip projections can be applied to other elements, such as aneedle. Applying a grip projection to the needle can, for example, allowa needle to be easily gripped and moved along a track as describedherein.

In some further embodiments, a modified sheath 26L, with somesimilarities to the previous sheaths discussed, can be combined with theother element described. As depicted in FIGS. 24A and 24B, the sheath26L can be a splittable sheath. As depicted, the sheath hub 42L can havetwo or more tabs 320 that can be gripped. The tabs 320 can then bepulled to split the splittable sheath 40L along a split line 330. Asdepicted, the split line 330 can extend through both the sheath hub 42Land the sheath body 40L. Thus, splitting the sheath 26L along the splitline 330 can separate the sheath into two halves. The sheath 26L alsocan have a lip 95, allowing engagement with other elements describedabove, such as the dilator 24, in a manner similar to the sheath 26.

The sheath hub 42L can additionally include a ridge 325 toward a distalend of the hub. The ridge 325 can facilitate gripping of the hub 42L.Additionally, in some embodiments the ridge 325 can receive a tubular orcylindrical cover that can extend over the distal portions of thesheath, dilator, and needle to protect the tip, and press onto the ridge325. Thus, the ridge 325 can hold the cover in place.

The embodiments herein described are comprised of conventional,biocompatible materials. For example, the needle preferably consists ofceramic, a rigid polymer, or a metal such as stainless steel, nitinol,or the like. The other elements can be formed of suitable polymericmaterials, such as polycarbonate, nylon, polyethylene, high-densitypolyethylene, polypropylene, fluoropolymers and copolymers such asperfluoro (ethylene-propylene) copolymer, polyurethane polymers orco-polymers. For example, in some embodiments the dilator can be formedfrom nylon.

As noted above, the present access device can be used to place acatheter at other locations within a patient's body. Thus, for example,but without limitation, the access device can be used as or with avariety of catheters to drain fluids from abscesses, to drain air from apneumotorax, and to access the peritoneal cavity. In such applications,body fluids flow into the viewing space to indicate when the needle hasbeen properly placed.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. For example, the general shape of theneedle hub depicted in FIG. 18D differs in additional ways from theneedle hub depicted in FIG. 2F. However, these general needle hub shapescan be interchanged between the described and depicted embodiments.Thus, it is intended that the scope of the present invention hereindisclosed should not be limited by the particular disclosed embodimentsdescribed above, but should be determined only by a fair reading of thedisclosure and the claims that follow.

What is claimed is:
 1. An access device for placing a medical articlewithin a body space, comprising: a needle having an elongated needlebody with a distal end and a needle hub from which the needle bodyextends; a dilator slideably disposed on the needle body and comprisinga dilator hub and an elongated dilator shaft that extends from thedilator hub to a distal end, the dilator hub comprising a receivingportion; and an insert disposed within the dilator hub and supported bythe receiving portion, the insert comprising a through-hole configuredto receive the needle body therethrough such that the needle body iscapable of extending through the insert, at least a portion of thethrough-hole being sized and shaped relative to the needle body so as toform a space between the insert and the needle body that allows gases topass through the space and to the atmosphere but hinders the passage ofa body fluid through the space.
 2. The access device of claim 1, whereinthe at least a portion of the through-hole is slightly larger than theneedle body.
 3. The access device of claim 1, wherein the elongatedneedle body comprises at least one fenestration in communication with achannel between the dilator shaft and the needle body.
 4. The accessdevice of claim 3 further comprising a medical article having a tubularsection and a hub, the tubular section being disposed on the dilator anddefining a second channel between the medical article and the dilator.5. The access device of claim 1, wherein the distal end of the dilatorhas a first taper and a second taper distal of the first taper, an angleof the second taper being different than an angle of the first taper. 6.The access device of claim 1, wherein the insert is press-fit in thereceiving portion.
 7. The access device of claim 1, wherein at least aportion of the through-hole tapers.
 8. The access device of claim 1,wherein the insert is sized and shaped to substantially match an innersurface of the receiving portion.
 9. The access device of claim 1,wherein the insert and an inner surface of the receiving portion aresized and shaped so that the insert is rotationally fixed within thereceiving portion.
 10. The access device of claim 1, wherein the insertcomprises a proximal face that faces the needle hub and comprises one ormore projections or grooves that can preserve a second space for gasesbetween the insert and the needle hub.
 11. The access device of claim 1,wherein a distal portion of the needle hub comprises a distal face thatfaces the insert and comprises one or more projections or groovesconfigured to preserve a second space for gases between the insert andthe needle hub.
 12. The access device of claim 1, wherein a distalportion of the dilator shaft comprises an inner diameter that is lessthan the outer diameter of the needle body.
 13. The access device ofclaim 1, wherein at least a part of an inner surface of the receivingportion comprises a taper.
 14. The access device of claim 1, wherein theneedle and dilator are moveable relative to each other from a firstposition, wherein the distal end of the needle body lies distal of thedilator, and a second position wherein the distal end of the needle bodylies within the dilator.
 15. The access device of claim 1 furthercomprising a locking mechanism operating between the needle and thedilator to inhibit movement of the needle relative to the dilator whenin the second position, the locking mechanism being configured to allowmovement of the needle from the first position toward the secondposition without engagement by the locking mechanism so as to lessenresistance to the movement.
 16. An access device for placing a medicalarticle within a body space, comprising: a needle having an elongatedneedle body with a distal end and a needle hub from which the needlebody extends; a dilator slideably disposed on the needle body andcomprising a dilator hub and an elongated dilator shaft that extendsfrom the dilator hub to a distal end, the dilator hub comprising areceiving portion; and an insert disposed within the dilator hub andsupported by the receiving portion, the insert comprising a through-holeconfigured to receive the needle body therethrough such that the needlebody is capable of extending through the insert, the insert configuredto allow gases to pass through the through-hole and to the atmospherebut hinder the passage of a body fluid through the through-hole when theneedle body extends therethrough, wherein the dilator, the needle, andthe insert define a space within the receiving portion, the spaceconfigured to allow gases to enter.
 17. The access device of claim 16,wherein the insert comprises one or more ridges or grooves.
 18. Theaccess device of claim 17, wherein the one or more ridges or grooves aredisposed in the through-hole.
 19. The access device of claim 18, whereinthe through-hole is slightly larger than the needle body at a locationof the one or more ridges or grooves.
 20. The access device of claim 19,wherein the needle hub comprises one or more ridges or grooves.